Requirements, some more additions

• New command argument for setting display names
• New cmd arg for renaming
• Convert old ; commas into per key config property for better readability
• Using DI (Dependency Injection) to track field/constructor changes for specific class, and to iterate over all players to replace all of available placeholders when setting display name. We solved temporarily with just iterating the players only once when the display name has been set, so some placeholders can be displayed without automatic refresh.
• Switching to integer identifier instead of names