v1.3.3 - Squad v2.12 Accommodation

A patch to accommodate some of the additions brought by Squad's v2.12 update and to resolve some issues.

Special thanks to @jneil1992 for his contributions to #10 and #14.

Changelogs:

• The player's current role is now included in the r!player command response and replaces the unused "Score" field
• Updated the list of factions and detachments including short names for both Squad and BTW
• Simplified some input errors when changing configs to make them more understandable for the average user
• Added additional aliases to commands so that "layer" can be used instead of "map" #14
• Fixed layer-related commands not working for Squad instances (r!set_next_map, r!change_map, custom map rotations) #14
• Fixed the r!set_player_limit command missing a parameter
• Fixed error raised when attempting to register two instances on the same IP address
• Updated list of PS and BTW maps #10