feat!: replace postgresql-ha with CloudNativePG

The bundled `postgresql-ha` sub-chart was the only HA-ready database option, but it pinned us to a Bitnami chart
whose images are no longer freely distributed, and it bundled repmgr and pgpool into the release. Operating a
Postgres cluster through a Helm release also means the chart has to reimplement failover, backup and upgrade
orchestration that a dedicated operator already solves.

CloudNativePG is the de-facto standard operator for Postgres on Kubernetes and handles instance management,
streaming replication, switchover and rolling upgrades itself. The operator is deliberately *not* part of this
chart: cluster-scoped CRDs and controllers do not belong into an application release and would conflict with an
operator that is already installed. The chart only renders the namespaced `Cluster` resource, so the operator can
be managed independently.

Because the operator cannot be assumed to be present, `cloudnativePG.enabled` defaults to `false`. Existing users
of `postgresql` or an external database are therefore unaffected.

Credentials follow the chart-wide `secrets.*` convention. Only the password is read from a Secret, because
CloudNativePG requires `bootstrap.initdb.database` and `bootstrap.initdb.owner` as literals in the `Cluster` spec
and cannot resolve them from a Secret. The password is injected into the `init-app-ini` container as
`GITEA__database__PASSWD` instead of being written into the generated `app.ini`.

BREAKING CHANGE: The `postgresql-ha` sub-chart and all `postgresql-ha.*` values have been removed. There is no
in-place migration path between the two deployments: dump the database of the old `postgresql-ha` release with
`pg_dump`, remove the `postgresql-ha` values, deploy the chart with `cloudnativePG.enabled=true` and restore the
dump. Setting `postgresql-ha` now fails the release with a pointer to the changelog.

Co-authored-by: Copilot <copilot@github.com>

unittests/helm/dependency-checks/customizationIntegrityPostgresql.yaml

@@ -3,7 +3,7 @@ release:
   name: gitea-unittests
   namespace: testing
 set:
-  postgresql-ha:
+  cloudnativePG:
     enabled: false
   postgresql:
     enabled: true

unittests/helm/dependency-checks/customizationIntegrityPostgresqlHA.yaml

@@ -1,129 +0,0 @@
-suite: Test dependency customization integrity of postgresql-ha
-release:
-  name: gitea-unittests
-  namespace: testing
-set:
-  postgresql:
-    enabled: false
-  postgresql-ha:
-    enabled: true
-    global:
-      postgresql:
-        database: gitea-database
-        password: gitea-password
-        username: gitea-username
-    postgresql:
-      repmgrPassword: custom-password-repmgr
-      postgresPassword: custom-password-postgres
-      password: custom-password-overwritten-by-global-postgresql-password
-    pgpool:
-      adminPassword: custom-password-pgpool
-      srCheckPassword: custom-password-sr-check
-    service:
-      ports:
-        postgresql: 1234
-    persistence:
-      size: 1337Mi
-tests:
-  - it: "[postgresql-ha] Apply the database settings"
-    template: charts/postgresql-ha/templates/postgresql/statefulset.yaml
-    asserts:
-      - documentIndex: 0
-        contains:
-          path: spec.template.spec.containers[0].env
-          content:
-            name: POSTGRES_DB
-            value: "gitea-database"
-      - documentIndex: 0
-        contains:
-          path: spec.template.spec.containers[0].env
-          content:
-            name: POSTGRES_USER
-            value: "gitea-username"
-  - it: "[postgresql-ha] Apply the database passwords"
-    template: charts/postgresql-ha/templates/postgresql/secrets.yaml
-    asserts:
-      - documentIndex: 0
-        equal:
-          path: data["repmgr-password"]
-          value: "Y3VzdG9tLXBhc3N3b3JkLXJlcG1ncg=="
-      - documentIndex: 0
-        equal:
-          path: data["postgres-password"]
-          value: "Y3VzdG9tLXBhc3N3b3JkLXBvc3RncmVz"
-      - documentIndex: 0
-        equal:
-          path: data["password"]
-          value: "Z2l0ZWEtcGFzc3dvcmQ=" # postgresql-ha.postgresql.password is overwritten by postgresql-ha.global.postgresql.password and should not be referenced here
-  - it: "[postgresql-ha] Apply pgpool.adminPassword"
-    template: charts/postgresql-ha/templates/pgpool/secrets.yaml
-    asserts:
-      - documentIndex: 0
-        equal:
-          path: data["admin-password"]
-          value: "Y3VzdG9tLXBhc3N3b3JkLXBncG9vbA=="
-  - it: "[postgresql-ha] Apply pgpool.srCheckPassword"
-    template: charts/postgresql-ha/templates/pgpool/secrets.yaml
-    asserts:
-      - documentIndex: 0
-        equal:
-          path: data["sr-check-password"]
-          value: "Y3VzdG9tLXBhc3N3b3JkLXNyLWNoZWNr"
-  - it: "[postgresql-ha] Apply persistence.size"
-    template: charts/postgresql-ha/templates/postgresql/statefulset.yaml
-    asserts:
-      - documentIndex: 0
-        equal:
-          path: spec.volumeClaimTemplates[0].spec.resources.requests.storage
-          value: "1337Mi"
-  - it: "[postgresql-ha] Apply service.ports.postgresql"
-    template: charts/postgresql-ha/templates/pgpool/service.yaml
-    asserts:
-      - documentIndex: 0
-        equal:
-          path: spec.ports[0].port
-          value: 1234
-  - it: "[postgresql-ha] Render the referenced Service"
-    template: charts/postgresql-ha/templates/pgpool/service.yaml
-    asserts:
-      - containsDocument:
-          kind: Service
-          apiVersion: v1
-          name: gitea-unittests-postgresql-ha-pgpool
-          namespace: testing
-  - it: "[gitea] Connect to the pgpool Service"
-    template: templates/secret_inlineConfig.yaml
-    asserts:
-      - documentIndex: 0
-        matchRegex:
-          path: data.database
-          decodeBase64: true
-          pattern: HOST=gitea-unittests-postgresql-ha-pgpool.testing.svc.cluster.local:1234
-  - it: "[gitea] Connect to the pgpool Service with a custom cluster domain"
-    set:
-      clusterDomain: my-special-cluster.local
-    template: templates/secret_inlineConfig.yaml
-    asserts:
-      - documentIndex: 0
-        matchRegex:
-          path: data.database
-          decodeBase64: true
-          pattern: HOST=gitea-unittests-postgresql-ha-pgpool.testing.svc.my-special-cluster.local:1234
-  - it: "[gitea] Connect to the configured database"
-    template: templates/secret_inlineConfig.yaml
-    asserts:
-      - documentIndex: 0
-        matchRegex:
-          path: data.database
-          decodeBase64: true
-          pattern: NAME=gitea-database
-      - documentIndex: 0
-        matchRegex:
-          path: data.database
-          decodeBase64: true
-          pattern: USER=gitea-username
-      - documentIndex: 0
-        matchRegex:
-          path: data.database
-          decodeBase64: true
-          pattern: PASSWD=gitea-password

unittests/helm/dependency-checks/majorImageBump.yaml

@@ -3,25 +3,12 @@ release:
   name: gitea-unittests
   namespace: testing
 tests:
-  - it: "[postgresql-ha] Detect major image version upgrades"
-    template: charts/postgresql-ha/templates/postgresql/statefulset.yaml
-    set:
-      postgresql:
-        enabled: false
-      postgresql-ha:
-        enabled: true
-    asserts:
-      - documentIndex: 0
-        matchRegex:
-          path: spec.template.spec.containers[0].image
-          # IN CASE OF AN INTENTIONAL MAJOR BUMP, ADJUST THIS TEST
-          pattern: bitnamilegacy/postgresql-repmgr:17.+$
   - it: "[postgresql] Detect major image version upgrades"
     template: charts/postgresql/templates/primary/statefulset.yaml
     set:
       postgresql:
         enabled: true
-      postgresql-ha:
+      cloudnativePG:
         enabled: false
     asserts:
       - documentIndex: 0