Allow disabling C2S ActivityPub API

Signed-off-by: marcin mikołajczak <git@mkljczk.pl>

config/config.exs

@@ -359,7 +359,8 @@ config :pleroma, :activitypub,
   follow_handshake_timeout: 500,
   note_replies_output_limit: 5,
   sign_object_fetches: true,
-  authorized_fetch_mode: false
+  authorized_fetch_mode: false,
+  client_api_enabled: true
 
 config :pleroma, :streamer,
   workers: 3,

config/description.exs

@@ -1772,6 +1772,11 @@ config :pleroma, :config_description, [
         type: :integer,
         description: "Following handshake timeout",
         suggestions: [500]
+      },
+      %{
+        key: :client_api_enabled,
+        type: :boolean,
+        description: "Allow client to server ActivityPub interactions"
       }
     ]
   },