Refs #15779 - make background processing unavailable for now (#4217)

The original PR got vetted in the packaging phase and including
foreman-task as dependency of Foreman was refused. We need to rethink
our approach for getting the foreman-tasks functionality available...

Fixes #17872 - Update button label from New to Create

Based on PatternFly Terminology and Wording suggestions
Don't recommend to use New, so update New to Create.

fixes #18214 - accept `params` as AC::Parameters or Hash

In Rails 5, ActionController::Parameters no longer inherits from Hash
and so type checks for params.is_a?(Hash) now return false and should
accept either. (Rails commit 14a3bd5.)

fixes #18157 - use AS::Duration division to get days from expiry

ActiveSupport::Duration#parts was an unreliable API as it contains data
used internally when constructing durations.

fixes #17545 - adds UI notification support

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

Fixes #6502 - List ignored classes and environments on import

When importing environments and classes from puppet, ignored
environments and classes defined in ignored_environments.yml
aren't aparent.

This will add them to the list to import as ignored and...

Fixes #6952 - Set hostgroup after provisioning from pxe

After hostgroup provisioning, when the machine has registered
with foreman, it should be in the same hostgroup.
to achieve this behavier, the fact foreman_hostgroup should be
added to hostgroup provisioning template

Fixes #16740 - Access host params through macro

Fixes #17894 - load needed dependent api param group

when rendering facet api param docs

Fixes #17874 - Extract contains_erb? from lookup key