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/controllers/api/v1/filters/statuses_controller.rb

@@ -0,0 +1,44 @@
+# frozen_string_literal: true
+
+class Api::V1::Filters::StatusesController < Api::BaseController
+  before_action -> { doorkeeper_authorize! :read, :'read:filters' }, only: [:index, :show]
+  before_action -> { doorkeeper_authorize! :write, :'write:filters' }, except: [:index, :show]
+  before_action :require_user!
+
+  before_action :set_status_filters, only: :index
+  before_action :set_status_filter, only: [:show, :destroy]
+
+  def index
+    render json: @status_filters, each_serializer: REST::FilterStatusSerializer
+  end
+
+  def create
+    @status_filter = current_account.custom_filters.find(params[:filter_id]).statuses.create!(resource_params)
+
+    render json: @status_filter, serializer: REST::FilterStatusSerializer
+  end
+
+  def show
+    render json: @status_filter, serializer: REST::FilterStatusSerializer
+  end
+
+  def destroy
+    @status_filter.destroy!
+    render_empty
+  end
+
+  private
+
+  def set_status_filters
+    filter = current_account.custom_filters.includes(:statuses).find(params[:filter_id])
+    @status_filters = filter.statuses
+  end
+
+  def set_status_filter
+    @status_filter = CustomFilterStatus.includes(:custom_filter).where(custom_filter: { account: current_account }).find(params[:id])
+  end
+
+  def resource_params
+    params.permit(:status_id)
+  end
+end