Merge branch 'hardening/stop-misusing-sharedinbox' into 'develop'

activitypub: publisher: align sharedinbox usage with AP specification rules

See merge request pleroma/pleroma!1464

diff --combined CHANGELOG.md
index bcdd0615fdf927dacd2654dffb1aee62c1fa395d,6d1c9ed31d3fe2175dec3e57c3e4ecbf7fed5379..6fcc8e390134185258d0a81cec3bc529de613088
--- 1/CHANGELOG.md
--- 2/CHANGELOG.md
+++ b/CHANGELOG.md
@@@ -19,10 -19,10 +19,11 @@@ The format is based on [Keep a Changelo
  - Mastodon API: Handling of search timeouts (`/api/v1/search` and `/api/v2/search`)
  - Mastodon API: Embedded relationships not being properly rendered in the Account entity of Status entity
  - Mastodon API: Add `account_id`, `type`, `offset`, and `limit` to search API (`/api/v1/search` and `/api/v2/search`)
 +- Mastodon API, streaming: Fix filtering of notifications based on blocks/mutes/thread mutes
  - ActivityPub C2S: follower/following collection pages being inaccessible even when authentifucated if `hide_followers`/ `hide_follows` was set
  - Existing user id not being preserved on insert conflict
  - Rich Media: Parser failing when no TTL can be found by image TTL setters
+ - ActivityPub S2S: sharedInbox usage has been mostly aligned with the rules in the AP specification.
  
  ### Added
  - MRF: Support for priming the mediaproxy cache (`Pleroma.Web.ActivityPub.MRF.MediaProxyWarmingPolicy`)