Switch to static URIs, new URI format in both protocols for new statuses (#4815)

* Decouple Status#local? from uri being nil

* Replace on-the-fly URI generation with stored URIs

- Generate URI in after_save hook for local statuses
- Use static value in TagManager when available, fallback to tag format
- Make TagManager use ActivityPub::TagManager to understand new format
- Adjust tests

* Use other heuristic for locality of old statuses, do not perform long query

* Exclude tombstone stream entries from Atom feed

* Prevent nil statuses from landing in Pubsubhubbub::DistributionWorker

* Fix URI not being saved (#4818)

* Add more specs for Status

* Save generated uri immediately

and also fix method order to minimize diff.

* Fix alternate HTML URL in Atom

* Fix tests

* Remove not-null constraint from statuses migration to speed it up

app/models/status.rb

@@ -22,6 +22,7 @@
 #  reblogs_count          :integer          default(0), not null
 #  language               :string
 #  conversation_id        :integer
+#  local                  :boolean          default(FALSE)
 #
 
 class Status < ApplicationRecord
@@ -84,7 +85,7 @@ class Status < ApplicationRecord
   end
 
   def local?
-    uri.nil?
+    attributes['local'] || uri.nil?
   end
 
   def reblog?
@@ -131,11 +132,14 @@ class Status < ApplicationRecord
     !sensitive? && media_attachments.any?
   end
 
+  after_create :store_uri, if: :local?
+
   before_validation :prepare_contents, if: :local?
   before_validation :set_reblog
   before_validation :set_visibility
   before_validation :set_conversation
   before_validation :set_sensitivity
+  before_validation :set_local
 
   class << self
     def not_in_filtered_languages(account)
@@ -253,6 +257,10 @@ class Status < ApplicationRecord
 
   private
 
+  def store_uri
+    update_attribute(:uri, ActivityPub::TagManager.instance.uri_for(self)) if uri.nil?
+  end
+
   def prepare_contents
     text&.strip!
     spoiler_text&.strip!
@@ -292,4 +300,8 @@ class Status < ApplicationRecord
       thread.account_id
     end
   end
+
+  def set_local
+    self.local = account.local?
+  end
 end