feat: enhance openshift support (#1063)

### Description of the change

Add options to values.yaml to make chart easier to install in restricted openshift environments

### Benefits

more people can run this

### Checklist

<!-- [Place an '[X]' (no spaces) in all applicable fields. Please remove unrelated fields.] -->

- [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)
- [ ] Breaking changes are documented in the `README.md`
- [x] Helm templating unittests are added (required when changing anything in `templates` folder)
- [ ] Bash unittests are added (required when changing anything in `scripts` folder)
- [x] All added template resources MUST render a namespace in metadata

---------

Co-authored-by: Lunny Xiao <xiaolunwen@gmail.com>
Reviewed-on: https://gitea.com/gitea/helm-gitea/pulls/1063
Reviewed-by: Lunny Xiao <xiaolunwen@gmail.com>
Co-authored-by: techknowlogick <techknowlogick@gitea.com>
Co-committed-by: techknowlogick <techknowlogick@gitea.com>

templates/tests/test-http-connection.yaml

@@ -9,9 +9,18 @@ metadata:
   annotations:
     "helm.sh/hook": test-success
 spec:
+  {{- $hostUsers := include "gitea.hostUsers" . | trim }}
+  {{- $testContainerSecurityContext := include "gitea.containerSecurityContext" (list . (dict)) | trim }}
+  {{- if $hostUsers }}
+  hostUsers: {{ $hostUsers }}
+  {{- end }}
   containers:
     - name: wget
       image: "{{ .Values.test.image.name }}:{{ .Values.test.image.tag }}"
+      {{- if $testContainerSecurityContext }}
+      securityContext:
+        {{- $testContainerSecurityContext | nindent 8 }}
+      {{- end }}
       command: ['wget']
       args:  ['{{ include "gitea.fullname" . }}-http:{{ .Values.service.http.port }}']
   restartPolicy: Never