misc: add ENABLE_PREJOIN_PAGE to .env

env.example

@@ -55,6 +55,9 @@ TZ=UTC
 # Control whether the lobby feature should be enabled or not
 #ENABLE_LOBBY=1
 
+# Show a prejoin page before entering a conference
+#ENABLE_PREJOIN_PAGE=0
+
 #
 # Let's Encrypt configuration
 #