Finish migration to v2 primitives

[rphmeier]

Closes #4803
Closes #4802

This removes v0 and v1 primitives, migrating everything to v2 instead. This also adds a RuntimeApiRequest::Version (currently, the runtime API subsystem handles versions internally, but it'd be better for that to be handled at the subsystem level after doing high-level version checks).

cumulus companion: paritytech/cumulus#1071

[rphmeier]

I've fully removed v0 and will remove v1 next (this one will get a bit tedious :) )

[rphmeier]

@ordian At some point we should be able to remove the storage migration and the #[changed_in(2)] version of the runtime API.

[rphmeier]

@sandreim is going to test on Versi & ZombieNet, and then we can merge 🎉

[sandreim]

Tested on Versi and ZombieNet and did not see any issues with parachain block production. I have observed some errors and warnings:

• offchain-worker txpool: (offchain call) Error submitting a transaction to the pool: Transaction pool error
• parachain::candidate-backing: Mpsc background validation mpsc died during validation- leaf no longer active? error=SendError { kind: Disconnected }

[rphmeier]

Neither of those seem related. Thank you for testing @sandreim

[ggwpez]

I think the cumulus companion did not merge, so cumulus does currently not build with polkadot master.
@rphmeier