Away mission refactoring
Created by: unid15
- Roundstart away missions must be enabled in the config now
- All away missions now exist as datums, just like vaults (this allows making more complex away missions with shuttles and other stuff without using voodoo magic)
- Admins can spawn away missions during the round (big ones can lag for half a minute)
- Added a "empty space" away mission for admins to spawn when they need an empty z-level
- Added a "Jump to Away Mission" admin verb. Works just like "Jump to Vault" or any other "jump to"
- If there are multiple away mission gateways, the station's gateway will teleport you to a random one.