chore(sizer): 🔧 rename forgejo-runner-sizer to ci-sizer in deployment configs

- Update container image names to ci-sizer-{receiver,collector}
- Update Dex OIDC client ID and name to ci-sizer
- Template allowed-org as SIZER_ALLOWED_ORG variable

otc/dev.t09.de/stacks/core/dex/values.yaml

@@ -79,8 +79,8 @@ config:
         - "https://grafana.dev.t09.de/login/generic_oauth"
       name: "Grafana"
       secretEnv: "OIDC_DEX_GRAFANA_CLIENT_SECRET"
-    - id: forgejo-runner-sizer
-      name: "Forgejo Runner Sizer"
+    - id: ci-sizer
+      name: "CI Sizer"
       redirectURIs:
         - "https://sizer.dev.t09.de/ui/callback"
       secretEnv: "FORGEJO_RUNNER_SIZER_CLIENT_SECRET"