Fen's RPG Titles

This update focuses on improving command usability, flexibility, and adding full localization support.

New features:

- Title descriptions are no longer mandatory when granting a title.

- Added support for an explicit description keyword in the grant command.
New command syntax:
/rtitle grant <player> <title>
/rtitle grant <player> <title> desc <description>

- Description is only applied when the "desc" keyword is used.

- Improved admin tab completion: when using /rtitle revoke <player>, tab completion now suggests only titles owned by the selected player.

- Added full localization support for all player-facing command messages.

- Added language files for English (en_us) and Russian (ru_ru).

Improvements:

- Reworked command structure to use proper Brigadier branching.

- Removed hardcoded command messages and replaced them with translatable components.

- Improved overall command clarity and usability for both players and administrators.

- Command logic is now easier to extend and maintain.

Fixes:

- Fixed incorrect tab completion in the revoke command that previously suggested titles of the command sender instead of the target player.

- Fixed forced title descriptions when granting titles.

- Improved error handling when command arguments are missing or incomplete.

Notes:

No configuration changes are required.

Existing titles and player data remain fully compatible.

Localization can be extended by adding new language files to the assets folder.