Replace room_invite_state_types with room_prejoin_state (#9700)

`room_invite_state_types` was inconvenient as a configuration setting, because
anyone that ever set it would not receive any new types that were added to the
defaults. Here, we deprecate the old setting, and replace it with a couple of
new settings under `room_prejoin_state`.

docker/conf/homeserver.yaml

@@ -173,18 +173,10 @@ report_stats: False
 
 ## API Configuration ##
 
-room_invite_state_types:
-    - "m.room.join_rules"
-    - "m.room.canonical_alias"
-    - "m.room.avatar"
-    - "m.room.name"
-
 {% if SYNAPSE_APPSERVICES %}
 app_service_config_files:
 {% for appservice in SYNAPSE_APPSERVICES %}    - "{{ appservice }}"
 {% endfor %}
-{% else %}
-app_service_config_files: []
 {% endif %}
 
 macaroon_secret_key: "{{ SYNAPSE_MACAROON_SECRET_KEY }}"