Fixes #14476 - Correctly handle casting of invalid real param values

Fixes #14232 - make generic helpers available for global PXE template

Fixes #14097 - Only run DatabaseCleaner truncation on JS tests

Problem:
DatabaseCleaner runs after all integration tests, on truncation mode.
However, for tests where we use rack-test instead of poltergeist, this
is not necessary and slows down the test suite....

fixes #14096 - handle MiB style memory units on statistics page

Fixes #13725 - DHCP MAC conflicts are reported

Fixes #13755 - allow reading of AR collections with safe mode enabled

Fixes #13557 - Rubocop enforce specifying a timezone

Rubocop can enforce what timezone to store in the database ,
so we can ensure everything is stored using UTC and we don't
miss these things in code reviews. When objects are displayed,
they must use the time provided by set_timezone in the...

fixes #13168 - permit safemode templates read-only access to AR relations

Templates such as kickstart_networking_setup use relations of
Host::Managed to access network interfaces. Since Rails 4, these return
relation objects rather than arrays which being core Ruby, had permitted...

fixes #13131 - plugin tests to skip is back

fixes #13039 - remove TemplateKind DB calls from UnattendedCtlr

UnattendedController created actions/methods during initialisation per
known TemplateKind, relying on the DB being populated. This caused
ordering issues when a plugin loaded the controller in a test...