Refs #32286 - setting DSL switch preparation

Removes some unused methods and tests.
This also add collections to the old collection registry to work before we hold them in registry only.

Fixes #32403 - Add validations to a setting DSL

Add ability to define validation per Setting through DSL.
It tries to keep similar syntax to rails model validations.

Fixes #31638 - Adds host status overview page

Fixes #31059 - drop Environment models

Refs #31059 - cleanup Environment from tests

Removes Environment related notes from tests, mostly just Host being
uselessly provided an environment.

Refs Refactor #31059: Extract Environments models - drop environments from User

Removes uses of Environment from User.

Extraction of `#visible_environments`:
https://github.com/theforeman/foreman_puppet/pull/126

Fixes #31095 - Remove config groups model

Added to the plugin in https://github.com/theforeman/foreman_puppet_enc/pull/12

Fixes #31235 - drop Puppetclass models

Drops Puppetclass models and their usage.
Extracted in https://github.com/theforeman/foreman_puppet_enc/pull/81
Tests extracted in:
- hostgroup - https://github.com/theforeman/foreman_puppet_enc/pull/85

Refs #30332 - drop ConfigGroupInfo

Extracted in https://github.com/theforeman/foreman_puppet_enc/pull/108

Fixes #31732 - drop environment in TemplateCombination model

Extract Environment from TemplateCombination matrix as temporary solutin.
This should probably get dropped if favor of some better solution like direct set on hostgroup.

Though this will need to be reflected in foreman_puppet_enc plugin....