Support group actor
Part of #656
Backend-wise:
- Ability to mark an actor as Group.
- Upon receiving an Object that has a local Group in its
to
field, boost it automatically if it is boostable. - If the local Group is only
cc
d, no boost is generated. - If the local Group has blocked the author of the Object, do not boost.
- If multiple local Groups are mentioned, it should generate multiple boosts.
Edited by tusooa