Improve command line support

[Rumsfield]

Player Commands

Add more text-based commands to supplement GUI-only features, like joining a kingdom. Having a text command is better for cross-plugin integration.

• [x] player chat commands for all menu actions
• [x] console support for most admin commands
• [x] update command references in language files

Console Commands

All commands currently require the send to be an in-game player, and most commands open inventory GUI menus for full control over plugin mechanics.

Add support for the console sender to be able to issue commands that affect plugin mechanics too, like:

• Kingdom & territory management
• Player membership management
• misc control...