Generic way for configuring Gitea app.ini (#240)

With the result of PR #239 it is much easier to provide additional values to the _app.ini_ configuration from different sources.
These changes adds an _additionalConfigSources_ field where the users can define such sources. This enables the users to choose
on their own whether to store values in _values.yaml_ or load them from Kuberetes Secrets or ConfigMaps.

- Fixes #243
- Fixes #174
- Fixes #260

Reviewed-on: https://gitea.com/gitea/helm-chart/pulls/240
Reviewed-by: luhahn <luhahn@noreply.gitea.io>
Reviewed-by: wxiaoguang <wxiaoguang@noreply.gitea.io>
Co-authored-by: justusbunsi <justusbunsi@noreply.gitea.io>
Co-committed-by: justusbunsi <justusbunsi@noreply.gitea.io>

templates/gitea/statefulset.yaml

@@ -97,6 +97,12 @@ spec:
               {{- if .Values.persistence.subPath }}
               subPath: {{ .Values.persistence.subPath }}
               {{- end }}
+            - name: inline-config-sources
+              mountPath: /env-to-ini-mounts/inlines/
+            {{- range $idx, $value := .Values.gitea.additionalConfigSources }}
+            - name: additional-config-sources-{{ $idx }}
+              mountPath: "/env-to-ini-mounts/additionals/{{ $idx }}/"
+            {{- end }}
             {{- if .Values.extraVolumeMounts }}
             {{- toYaml .Values.extraVolumeMounts | nindent 12 }}
             {{- end }}
@@ -284,6 +290,13 @@ spec:
         {{- if .Values.extraVolumes }}
         {{- toYaml .Values.extraVolumes | nindent 8 }}
         {{- end }}
+        - name: inline-config-sources
+          secret:
+            secretName: {{ include "gitea.fullname" . }}-inline-config
+        {{- range $idx, $value := .Values.gitea.additionalConfigSources }}
+        - name: additional-config-sources-{{ $idx }}
+          {{- toYaml $value | nindent 10 }}
+        {{- end }}
         - name: temp
           emptyDir: {}
   {{- if and .Values.persistence.enabled .Values.persistence.existingClaim }}