[#468] Merged `upstream/develop`.

.gitlab-ci.yml

config/config.exs

config/test.exs

docs/Differences-in-MastodonAPI-Responses.md

docs/Pleroma-API.md

docs/config.md

lib/pleroma/application.ex

lib/pleroma/jobs.ex

lib/pleroma/user.ex

lib/pleroma/user/info.ex

lib/pleroma/web/activity_pub/activity_pub.ex

lib/pleroma/web/activity_pub/activity_pub_controller.ex

lib/pleroma/web/activity_pub/mrf/hellthread_policy.ex

lib/pleroma/web/activity_pub/transmogrifier.ex

lib/pleroma/web/activity_pub/utils.ex

lib/pleroma/web/common_api/common_api.ex

lib/pleroma/web/common_api/utils.ex

lib/pleroma/web/federator/federator.ex

lib/pleroma/web/mastodon_api/mastodon_api_controller.ex

lib/pleroma/web/mastodon_api/views/status_view.ex