Fixes #16782 - reset dhcp record cache after mac change

(cherry picked from commit 969832057c5ea6a1f84eaf5c53f5cdc7ee445af2)

Fixes #17343 - set deep munge config off

deep_munge was introduced as a solution to keep
Rails secure by default which results in
'empty array becomes nil in params'.
Thats why, set deep_munge config off in application.rb.
Also, added changes which will cast param argument to string...

fixes #17071 - set ip after acquiring compute details

fixes #17197 - don't update DNS on ip6 change to empty string

fixes #16951 - ipv6 compute orchestration

fixes #16819 - rebuild tftp with template kinds

Fixes #16439 - Don't fail recreate if DNS is ok

If rebuilding a host and DNS is not "feasible" we don't want to fail
that host but rather recreate what's currently feasible.

If a DNS record is still valid we don't want to fail that host but
rather take the still valid entry.

fixes #15590 - ipv6 tftp orchestration

refs #12634 - remove blank i18n string, match capitalisation

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...