When first users (QAs) started testing & using Global Registration feature, they were repeatedly facing some issues with usability:

1. Forgetting to assign Host registration template (HRT) to operating system
2. Assigning Global Registration Template (GRT) to OS (instead of HRT)
3. Mixing GRT & HRT in general

Fix for 1. case:
When OS is created, automatically assign default HRT (defined in settings)
Assigned HRT to the OS is precondition for sucessful host registration to the Foreman. Without it process will always fail!
Therefore users have to assign template manually each time they create OS.

If they have to do it manually every single time OS is created,
we could do it for them, right? Like we do it in Katello plugin (https://github.com/Katello/katello/pull/9049),
but for all operating systems.

Fix for case 2. & 3.:
There are two new template kinds now (instead of just one):

• Global Registration template, (now with validation that it can't be assigned to OS)
• Host Registration template

And new setting for default host registration template