Refs #37034 - Use apt-key add on Ubuntu 16.04

• On Ubuntu 16.04, which is supported by Canonical until 2026, you
  cannot place a GPG public key in "/etc/apt/trusted.gpg.d/" and use it
  to verify the signature of "Release" files.
• EoL Ubuntu 16.04: https://ubuntu.com/16-04...

Fixes #37193 - trap ERR not supported on dash

Fixes #37189 - Registration before & after snippets

before_registration & after_registration snippets allow
users to add their code to the template without directly editing it.

Fixes #37034 - Replace apt-key on Debian/Ubuntu

Fixes #36747 - create new snippet for subscription-manager setup

This snippet replaces the use of the katello-ca-consumer RPM for host
registration. It incorporates the necessary code from the Global Registration
template to streamline subscription-manager configuration during provisioning.

Fixes #36938 - Ignore output of some commands in Global Registration

Fixes #36393 - Do not rebuild managed hosts in registration

Fixes #36293 - Use a stricter regex

replace sed with grep

Fixes #36071 - Registration - Unregister host before CA change

Moving subscribed / registered host from Foreman#1 to Foreman#2
cause SSL issues with subscription-manager unregister command.

Fix is to un-register host from Foreman#1 first,
then update CA for Foreman#2 and register host again.

Fixes #35645 - install and use sub-man for SLES OS during host-reg