hidden infra provider support

[Unix4ever]

Infra provider used for managed control planes shouldn't be usable by the user.
Validation should block using the infra provider in the machine classes/machine requests/machine request sets.

The provider should be readonly.
We can filter some data from the infra provider status if we have secrets there.

Managed control planes infra provider logs shouldn't be available to the end user when we get them implemented.

The infra provider will be labeled with omni.sidero.dev/managed and it will make it readonly and not usable by machine classes and machine requests.