With Coretime enabled we can no longer assume there is a static 1:1
mapping between core index and para id. This mapping should be obtained
from the scheduler/claimqueue on block by block basis.

This PR modifies `para_id()` (from `CoreState`) to return the scheduled
`ParaId` for occupied cores and removes its usages in the code.

Closes https://github.com/paritytech/polkadot-sdk/issues/3948



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Co-authored-by: Andrei Sandu <[email protected]>

Runtime release 1.2 includes bumping of the ParachainHost APIs up to
v10, so let's move all the released APIs out of vstaging folder, this PR
does not include any logic changes only renaming of the modules and some
moving around.

Signed-off-by: Alexandru Gheorghe <[email protected]>