Discord webhook posts links to arcomm.co/hub/ instead of arcomm.co.uk/hub/ for new missions

[Freddo3000]

[puzzleddev]

This comes down to Missions.php:235 which is the source for all mission URLs. It uses the Laravel url function, which uses the current request's schema, and hostname.

I am not sure what other parts of this codebase use this function, but if a canonical hostname is desired it should probably be implemented globally. This is, seemingly, not supported by Laravel and would, as such, require a number of individual changes.