Add customizable user roles (#18641)

* Add customizable user roles

* Various fixes and improvements

* Add migration for old settings and fix tootctl role management

spec/controllers/admin/domain_blocks_controller_spec.rb

@@ -4,7 +4,7 @@ RSpec.describe Admin::DomainBlocksController, type: :controller do
   render_views
 
   before do
-    sign_in Fabricate(:user, admin: true), scope: :user
+    sign_in Fabricate(:user, role: UserRole.find_by(name: 'Admin')), scope: :user
   end
 
   describe 'GET #new' do