Add semi-support for Video/Image objects in ActivityPub (#5848)

* Add semi-support for Video/Image objects in ActivityPub

Video and Image objects will create corresponding status records
with manually crafted text contents (title + URL)

* Extract html-url-finding logic into JsonLdHelper

* Fallback to id when url missing, extract supported object types

app/services/activitypub/fetch_remote_status_service.rb

@@ -42,7 +42,7 @@ class ActivityPub::FetchRemoteStatusService < BaseService
   end
 
   def expected_type?
-    %w(Note Article).include? @json['type']
+    (ActivityPub::Activity::Create::SUPPORTED_TYPES + ActivityPub::Activity::Create::CONVERTED_TYPES).include? @json['type']
   end
 
   def needs_update(actor)