Fixes #4608 - Added description field to role

Fixes #16643 - Display origin for facts

This commit sets the interfaces for the fact importers to start setting
a Fact origin, and display it in the UI

Fixes #16565 - Correct host search by parameters

Overrides for parameters values caused incorrect results for when
searching by parameter value. This commit fixes those results, and
improves the handling of parameter priorities in general. A new rake
task, `parameters:reset_priorities` is introduced that should be invoked...

Fixes #15846 - Renamed use_puppet_default to omit in LookupValue

templates - sync from community-templates

Refs #15814 - Reset override params only for PuppetclassLookupKey

Fixes #16384 - Localize the names for email prefs

Two changes were made to support this:

1) The seed file which loads the notifications to the db was
augmented to add in the translated forms of the name.
2) The ui was enhanced to use gettext to look up the translations.

Fixes #14468 - fix db:migrate when unattended false on empty db

Fixes #7806 - allow taxonomy association on role level

Fixes #12634 - New HW Model flag pxe_loader

Implementation of

https://github.com/theforeman/rfcs/blob/master/text/0001-PXE-Booting-UEFI.md

In short, new host/hostgroup flag PXE loader is added to specify TFTP
DHCP filename and Foreman now orchestrates all PXE-capable templates...