Fixes #19789 - fix Layout/SpaceAroundOperators cop

Fixes #22601 - Update Rails to 5.1.6

Fixes #23169 - Orders settings alphabetically

Fixes #19781 - Fix Layout/LeadingCommentSpace cop

Fixes #19787 - Fix Layout/SpaceAfterComma cop

Fixes #22096 - Make Audits taxable (#5269)

Fixes #22721 - Rename setting to trusted_hosts

The setting trusted_puppetmaster_hosts is used to allow hosts to submit
stuff to the facts/reports API endpoint.
The name made sense a long time ago, but these days other plugins and
any user can submit stuff to this API to generate...

Fixes #22355 - Make stripping a setting value optional

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 #21238 - Settings - show defaults on hover

Refs #19050 - Update Rails 5.0 to 5.0.6

Fixes #17204 - Sort setting UI category tabs consistently

fixes #18200 - don't re-encrypt settings when value is unchanged

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 #17588 - Remove 1.16 deprecations

show_taxonomy_tabs helper, Settings.method helper and email.yaml support

Fixes #14013 - add a setting for default owner of new hosts

Fixes #17330 - skip admin email if it's unknown

When admin user is being seeded the Setting might not exist at that
moment. We can't just create it with value, since the setting would
be invalid because of other attributes. Therefore we split settings
creation from the setting list so we could create it from seed too....

Fixes #13870 - encrypt specific settings values in db

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...