Support active effects for vehicle equipment

[aaclayton]

Originally in GitLab by @ohporter

1. Add Effects tab to the vehicle sheet (done with !351)
2. Allow configuration of base AC and use of a vehicle formula rather than just flat AC, so AC bonuses can be applied by active effects
3. vehicle equipment items can not be equipped/attuned via the sheet UI as they are isMountable and don't expose those options. The prohibits transfer of active effects. Either allow equipped/attuned or make an exception case for some types of items to transfer effects when not equipped/attuned.