Move create/destroy actions for api/v1/statuses to namespace (#3678)

Each of mute, favourite, reblog has been updated to:

- Have a separate controller with just a create and destroy action
- Preserve historical route names to not break the API
- Mild refactoring to break up long methods

app/controllers/api/v1/statuses/favourites_controller.rb

@@ -0,0 +1,38 @@
+# frozen_string_literal: true
+
+class Api::V1::Statuses::FavouritesController < Api::BaseController
+  include Authorization
+
+  before_action -> { doorkeeper_authorize! :write }
+  before_action :require_user!
+
+  respond_to :json
+
+  def create
+    @status = favourited_status
+    render 'api/v1/statuses/show'
+  end
+
+  def destroy
+    @status = requested_status
+    @favourites_map = { @status.id => false }
+
+    UnfavouriteWorker.perform_async(current_user.account_id, @status.id)
+
+    render 'api/v1/statuses/show'
+  end
+
+  private
+
+  def favourited_status
+    service_result.status.reload
+  end
+
+  def service_result
+    FavouriteService.new.call(current_user.account, requested_status)
+  end
+
+  def requested_status
+    Status.find(params[:status_id])
+  end
+end