Sort pb cmake and add comments to proto files (#6163)

* sort cmake

* copy over comments

* clean up comments

common/pb/event_game_state_changed.proto

@@ -2,13 +2,26 @@ syntax = "proto2";
 import "game_event.proto";
 import "serverinfo_player.proto";
 
+// Signals that the game state has changed.
+// If a field is present in this message, it will overwrite the client's game state.
+// Also used to provide the entire game state when joining a game.
 message Event_GameStateChanged {
     extend GameEvent {
         optional Event_GameStateChanged ext = 1005;
     }
+
+    // the list of players. Players contain their zones which contain all cards in the game
     repeated ServerInfo_Player player_list = 1;
+
+    // if the game has started
     optional bool game_started = 2;
+
+    // the player who is currently holding the turn
     optional sint32 active_player_id = 3;
+
+    // the current phase
     optional sint32 active_phase = 4;
+
+    // the amount of seconds since the game started
     optional uint32 seconds_elapsed = 5;
 }