Merge branch 'feature/1482-activity_pub_transactions' into 'develop'

ActivityPub actions & side-effects in transaction

Closes #1482

See merge request pleroma/pleroma!2089

diff --cc lib/pleroma/object.ex
Simple merge

diff --cc lib/pleroma/pagination.ex
Simple merge

diff --cc lib/pleroma/user.ex
Simple merge

diff --cc lib/pleroma/web/activity_pub/activity_pub.ex
Simple merge

diff --cc test/web/activity_pub/activity_pub_test.exs
Simple merge