Fixes #19789 - fix Layout/SpaceAroundOperators cop

Refs #22164 - use cheaper FactoryBot methods

• Refs #22164 - FactoryBot.build -> FactoryBot.build_stubbed

• Refs #22164 - FactoryBot.create -> FactoryBot.build

in
- test/unit/*
- test/models/shared/taxonomies_base_test.rb
- test/controllers/hosts_controller_test.rb

Fixes #21424 - use factory_bot_rails

fixes #16557 - move tests into modern Rails layout

Models, controllers, mailers and helpers are now in test/ subdirs
matching app/ subdirs. Service, miscellaneous and old test/lib/ tests
are now in test/unit/ separated from models, which obsoletes the custom...