Make test pods optional and allow image override (#360)

### Description of the change

Make the test-connection Pod optional and override the wget container's image.

### Benefits

Allows users to enable/disabled the test-connection Pod and override the wget container's image.

### Checklist

- [X] Parameters are documented in the `values.yaml` and added to the `README.md` using [readme-generator-for-helm](https://github.com/bitnami-labs/readme-generator-for-helm)
- [X] Breaking changes are documented in the `README.md`

Co-authored-by: Umer Anwar <umer.anwar@nuance.com>
Co-authored-by: ooms97 <anwarumer97@gmail.com>
Reviewed-on: https://gitea.com/gitea/helm-chart/pulls/360
Reviewed-by: pat-s <pat-s@noreply.gitea.io>
Reviewed-by: justusbunsi <justusbunsi@noreply.gitea.io>
Co-authored-by: ooms97 <ooms97@noreply.gitea.io>
Co-committed-by: ooms97 <ooms97@noreply.gitea.io>

templates/tests/test-http-connection.yaml

@@ -1,3 +1,4 @@
+{{- if .Values.test.enabled }}
 apiVersion: v1
 kind: Pod
 metadata:
@@ -9,7 +10,8 @@ metadata:
 spec:
   containers:
     - name: wget
-      image: busybox
+      image: "{{ .Values.test.image.name }}:{{ .Values.test.image.tag }}"
       command: ['wget']
       args:  ['{{ include "gitea.fullname" . }}-http:{{ .Values.service.http.port }}']
   restartPolicy: Never
+{{- end }}