Fixes #24125 - Show error when libvirt not reachable

Fixes #19789 - fix Layout/SpaceAroundOperators cop

Fixes #23859 - Fix vm_exists? method

Fix related tests

Fixes #23254 - Utilize webmock to prevent network connection

in tests

Fixes #19879 - Fix Style/NestedParenthesizedCalls 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 #19131 - upgrade minitest to latest 5.x

- override minitest's `_` expectation method with the gettext method
- rename `location` let helper, conflicted with a minitest method name
- fix `assert_equal nil, [..]` deprecation warnings, prefer `assert nil`...

fixes #17533 - provision dhcp for bond child macs

Fixes #16782 - reset dhcp record cache after mac change

fixes #17071 - set ip after acquiring compute details

fixes #16951 - ipv6 compute orchestration

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...