[TownyCaptureSites] Suggestion: Nation involvement

[tomhmagic]

Please explain your feature request to the best of your abilities:

It would be amazing if we could add nation involvement in capture sites.
Allowing players in town to carry on as normal, but nations could choose to capture as a nation. You can even make it so some capturesites are town only or nation only or both. When a nation holds a capturesite, the nation received the defined reward for that nation.

Commands:
/n capture
/n defend
/ta capturesite type town/nation/both

Involvement Priority:
Town holds site = Only attacking town
Nation holds site = Only attacking town, unless attacking town is part of a nation, then whole nation can attack

Config Options:
You should be able to set the config options separate depending on if a town or nation holds the site.

As an added bonus, it would be amazing, if all the config options where a "set default", and these options could be changed in a per site config, either directly in a save file in the site folder, or adding in game commands. This will allow the ability to design different capturesite types and difficulties with higher reward.