Fixes #18025 - make user groups sortable

Fixes #18031 - unify admin flag label

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 #18024 - add 'image' search field to hosts

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 #17972 - Simplify new trend form js and helpers

Migrated the js to webpack as well.

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 #17438 - Disable selecting IPv6 on import

Fixes #16782 - reset dhcp record cache after mac change

Fixes #17864 - Show smart proxy errors on unattended fail

If your proxy is has some error (like misconfigured sudoers, puppet not
available, etc...) and you try to boot a host through unattended
mode [1], the exception will not show up when you try to fetch the...