Introduce Limits headers. (#15329)

* Move RCT12 limits to seperate file and namespace

* Remove prefix from constants

* Add rct1 limits file

* Rename constants to remove prefix

* Add RCT2 limits file

* Remove RCT2 prefix from constants

* Move constant to correct header

* Fix rebase mistakes

* Drop prefix

src/openrct2/Game.cpp

@@ -397,7 +397,7 @@ void game_convert_strings_to_rct2(rct_s6_data* s6)
     {
         if (!str_is_null_or_empty(userString))
         {
-            utf8_to_rct2_self(userString, RCT12_USER_STRING_MAX_LENGTH);
+            utf8_to_rct2_self(userString, RCT12::Limits::MaxUserStringLength);
         }
     }
 }