Move validations into PackageProtections.validate!

[alexevanczuk]

There are many validations that show up to the user when we use PackageProtections APIs like PackageProtections::ProtectedPackage.from(...).

These validations all require that the user set up PackageProtections up correctly.

As we move away from package_proteections and to rubocop-packs, we want to allow packs to opt-out of package protections validations more easily.
To do that, we move all validations into one place. This will also stop validations from happening during modularization_statistics execution, so users can use modularization_statistics without having configured package_protections.