prosody: add support for A/V Moderation

Set ENABLE_AV_MODERATION to 1 in order to enable it.

NOTE: This feature is still under development and should be considered
beta quality.

env.example

@@ -52,6 +52,9 @@ TZ=UTC
 # Control whether the lobby feature should be enabled or not
 #ENABLE_LOBBY=1
 
+# Control whether the A/V moderation should be enabled or not
+#ENABLE_AV_MODERATION=1
+
 # Show a prejoin page before entering a conference
 #ENABLE_PREJOIN_PAGE=0