Add ability to filter individual posts (#18945)

* Add database table for status-specific filters

* Add REST endpoints, entities and attributes

* Show status filters in /filters interface

* Perform server-side filtering for individual posts filters

* Fix filtering on context mismatch

* Refactor `toServerSideType` by moving it to its own module

* Move loupe and delete icons to their own module

* Add ability to filter individual posts from WebUI

* Replace keyword list by warnings (expired, context mismatch)

* Refactor server-side filtering code

* Add tests

app/serializers/rest/filter_result_serializer.rb

@@ -3,4 +3,9 @@
 class REST::FilterResultSerializer < ActiveModel::Serializer
   belongs_to :filter, serializer: REST::FilterSerializer
   has_many :keyword_matches
+  has_many :status_matches
+
+  def status_matches
+    object.status_matches&.map(&:to_s)
+  end
 end

app/serializers/rest/filter_serializer.rb

@@ -3,6 +3,7 @@
 class REST::FilterSerializer < ActiveModel::Serializer
   attributes :id, :title, :context, :expires_at, :filter_action
   has_many :keywords, serializer: REST::FilterKeywordSerializer, if: :rules_requested?
+  has_many :statuses, serializer: REST::FilterStatusSerializer, if: :rules_requested?
 
   def id
     object.id.to_s

app/serializers/rest/filter_status_serializer.rb

@@ -0,0 +1,13 @@
+# frozen_string_literal: true
+
+class REST::FilterStatusSerializer < ActiveModel::Serializer
+  attributes :id, :status_id
+
+  def id
+    object.id.to_s
+  end
+
+  def status_id
+    object.status_id.to_s
+  end
+end