multistreaming: scenes/composition, installer build support, service updates

- multistreaming (new): RTMP ingest + multi-platform fan-out with pluggable providers (Twitch/YouTube/Kick/custom), zero-knowledge key vaults, Authelia OIDC auth, shared rooms with editor/streamer roles, single-use invites, per-account streaming grants, and scenes & composition (grid/PiP layouts, text/image overlays, per-output audio routing).
- installer: support Dockerfile build in metadata (not just image) and RSA key generation for the Authelia OIDC JWKS.
- authelia: add OIDC provider with portainer + multistreaming clients (public + PKCE).
- services: remove allprox; add nginx-proxy-manager and portainer; update lldap; regenerate catalog.

services/multistreaming/.dockerignore

@@ -0,0 +1,13 @@
+node_modules
+web/node_modules
+web/dist
+.smoke-data
+data
+*.log
+.git
+.gitignore
+metadata.json
+docker-compose.yml
+.env
+Dockerfile
+.dockerignore