prosody: add ability to configure MUC modules through ENV variables

This allows for configuring how MUC modules can be used.

Closes: https://github.com/jitsi/docker-jitsi-meet/issues/1310

docker-compose.yml

@@ -218,6 +218,7 @@ services:
             - XMPP_INTERNAL_MUC_DOMAIN
             - XMPP_MODULES
             - XMPP_MUC_MODULES
+            - XMPP_MUC_CONFIGURATION
             - XMPP_INTERNAL_MUC_MODULES
             - XMPP_RECORDER_DOMAIN
             - XMPP_PORT

prosody/rootfs/defaults/conf.d/jitsi-meet.cfg.lua

@@ -243,6 +243,9 @@ Component "{{ $XMPP_MUC_DOMAIN }}" "muc"
     muc_room_cache_size = 1000
     muc_room_locking = false
     muc_room_default_public_jids = true
+    {{ if .Env.XMPP_MUC_CONFIGURATION -}}
+    "{{ join "\"\n\"" (splitList "," .Env.XMPP_MUC_CONFIGURATION) }}";
+    {{ end -}}
 
 Component "focus.{{ $XMPP_DOMAIN }}" "client_proxy"
     target_address = "{{ $JICOFO_AUTH_USER }}@{{ $XMPP_AUTH_DOMAIN }}"