[6.x] Refactor validation to use laravel-ruleset-validation

[riasvdv]

Description

This reworks the cms validation to work with the new laravel-ruleset-validation package.

• Any previously defined rulesets now extend a small base class which provides an additional event, all other logic is handled through the package
• Component validation is no longer handled separately, there is a simple ComponentRules ruleset which forwards calls onto the component for defined rules, messages and attribute labels.
• Scenarios no longer live on the component, they are handled by the rulesets, constants have been moved. Legacy classes now define the constants as well for backwards compatibility.