refactor(limits): server limits in one file, own texts for unknown errors

src/utils/manualGames.js

@@ -7,9 +7,6 @@ const JSON_HEADERS = {'Content-Type': 'application/json'};
 // positive keys; Auth also takes only those as background or banner.
 export const isSteamKey = (appid) => Number(appid) > 0;
 
-// Core's limit of a game's platform (ManualGameUpdate.MAX_PLATFORM_LENGTH).
-export const MAX_PLATFORM_LENGTH = 32;
-
 // Two decimals: then hoursToMinutes gives back the same minute.
 export const toHours = (minutes) => (minutes > 0 ? String(Math.round((minutes / 60) * 100) / 100) : '');