Contracts migration logic

[Dinonard]

Pull Request Summary

Context

pallet-contracts v9 storage migration can blow up in PoV size and this happened with Shibuya.
This PR provides an approach to migrate the storage in multiple steps.

• I wanted to avoid forking the pallet-contracts and doing the modification directly in there
• Most of the types needed from pallet-contracts are only available to pallet-contracts crate so they had to be redefined here

NOTE
It seems that PoV size is overestimated in the code (double the size we got with Shibuya upgrade).
As long as it's not underestimated it should be fine.

INFO main try-runtime::cli: TryRuntime_on_runtime_upgrade executed without errors. Consumed weight = (79450000000 ps, 47731515 byte), total weight = (500000000000 ps, 5242880 byte) (15.89 %, 910.41 %).

Check list

• implement solution & test it
• update Shiden too
• updated spec version
• updated semver

[Dinonard]

Functionally correct but doesn't account for PoV issue.
paritytech/substrate#12908

If attempting to reproduce locally, please keep in mind that there's a bug in pallet-contracts related to try-runtime.
The fix: paritytech/substrate#12905

[0x7CFE]

LGTM