Fixes #18280 - Adds compute resource provider name

Makes the API return the provider name of the compute resource

fixes #18102 - a host cannot be backed by the same vm

Fixes #17526 - Taxonomy.ignore? does not work with "any context"

In this scenario:

1. User has one organization - "E-Corp" - this organization allows the
user to see every hostgroup (via selecting "all host groups" when
editing the organization).

2. User has a location "Czech republic" that also includes all host...

fixes #18238 - use fixed model name in test expectation

Fixes #16752 - Extract template code from Host::Managed

Host::Managed contains a lot of code related with determining the
template that a host should have. Other Host objects such as
Host::Discovered might need that logic, without becoming a
Host::Managed....

fixes #18176 - replace clear_association_cache with reload

Reload is still necessary in Rails 5 as interfaces association will be
cached. The BMC test change is necessary to reload smart proxies
associated to the subnet after their features were altered - previously...

fixes #17545 - adds UI notification support

- Initial data model for notification support, based on manageiq design.
- addes notification JSON endpoints.

Fixes #3551 - Show unavailable Puppet Classes in Host Group edit

Puppet Classes can be assigned to a Host Group even if they are
not available in the set environment.

The Classes persist through out changes of the environment,
but were previously hidden from the UI this changes that....

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 #16782 - reset dhcp record cache after mac change