Deprecate @stable repo, fails installing

Nextcloud fails to install on our OAS pipeline. This MR deprecates thei
`@stable` repo and uses the proper repo URLs.

.gitlint

+[general]
+ignore=body-is-missing

requirements.yaml

@@ -2,26 +2,26 @@
 dependencies:
   - name: nextcloud
     version: 1.10.1
-    repository: "@stable"
+    repository: "https://nextcloud.github.io/helm/"
     tags:
       - nextcloud
   - name: rabbitmq
     version: 6.18.2
-    repository: "@stable"
+    repository: "https://charts.bitnami.com/bitnami"
     tags:
       - onlyoffice
       - rabbitmq
       - queue
   - name: redis
     version: 10.5.7
-    repository: "@stable"
+    repository: "https://charts.bitnami.com/bitnami"
     tags:
       - key-value-store
       - redis
       - onlyoffice
   - name: postgresql
     version: 8.6.4
-    repository: "@stable"
+    repository: "https://charts.bitnami.com/bitnami"
     tags:
       - postgresql
       - onlyoffice