Starlight: Wire ContainerRegistrar and Registrar pallets

[Agusrodri]

What does it do?

This PR combines the way in which ContainerRegistrar and Registrar pallets work together inside the starlight runtime.

It does so by introducing a new config type to the ContainerRegistrar pallet called InnerRegistrar, which acts as a callback that executes different behaviors depending on the function context we are situating on.

For instance:

• When calling ContainerRegistrar::register(), the InnerRegistrar internally calls Registrar::register() after performing the necessary checks and building the proper components (HeadData and ValidationCode).
• When calling ContainerRegistrar::deregister(), the InnerRegistrar takes care of also deregistering the paraId inside Registrar pallet.
• When calling ContainerRegistrar::mark_valid_for_collating(), the InnerRegistrar automatically upgrades the paraId to a parachain (in case it was a parathread) at the end of the function execution.

Other changes

• Added a new head_data parameter to ContainerRegistrar::register function and related ones that is used at the moment of registering a paraId in Registrar relay pallet.

Note for reviewers

There are a lot of changes in different tests, but the most important are the ones related to starlight itself (inisde solo-chains/runtime/starlight/src/tests).

The rest of the test changes are mostly to adapt to the new head_data parameter inside ContainerRegistrar::register and related functions.

[girazoki]

Good job @Agusrodri