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

Fixes #14492 - Unify delete and minimize for dashboard widgets

Originally the idea was for the buttons to have a different effect on
the widgets, however with changes introduced later on these differences
have been reduced to being insignificant.

fixes #18662 - stop default scope being overridden by association

Ensure the Taxonomix empty default scope isn't overridden by association
scopes which (effectively) calls `.where(:id => ...)` and overrides the
value of :id set in this default scope. This occurs on Rails 5.0 which...

refs #16982 - remove User.current deassignment (no such user)

Allows the scope change to be reverted, as User.current is no longer set
to `nil` (there is no 'admin' user).

This was relying on a bug in Ruby on Rails 4.2 where the `unscoped` call
filtered through thread variables into Subnet.subnet_for which calls...

Fixes #17272 - Fixed Searches on parameters with !=

Fixes #16982 - Scope properly when no taxonomies are set

The default scope for hosts and other objects did not restrict
properly by taxonomies. An user without organizations or
locations, could do anything it's permissions allow to.
The list of hosts was unrestricted and showed hosts in...

fixes #17533 - provision dhcp for bond child macs

fixes #18540 - update domain on primary in hosts_count tests

domain/domain_id are not attributes of the host itself, they're
delegated to the primary interface. When using update_attribute on the
host, the model doesn't appear `changed?` so Rails 5 skips the save....

fixes #18373 - vmware: do not pass automatic firmware to vm

fixes #18216 - volume size editable for existing VMs one