Add the Polkadot Coretime chain in advance of the 1.3.0 release.

This uses the new Price adapter which has been running on Kusama now for
two sales cycles, and includes the mechanism to burn revenue.

TODO:
- [x] Add Transact tests for hardcoded weights after
polkadot-fellows#401 is merged
- [ ] Rerun benchmarks and check hardcoded weights after merge

The genesis chain-spec is developing on
#4. This can be used as a merge
target for any community boot nodes who would like to be included at
genesis and will be separately merged to `main`.

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Co-authored-by: Bastian Köcher <git@kchr.de>
Co-authored-by: Branislav Kontur <bkontur@gmail.com>
Co-authored-by: fellowship-merge-bot[bot] <151052383+fellowship-merge-bot[bot]@users.noreply.github.com>

Remove migrations already **applied on-chain**.

- [x] Does not require a CHANGELOG entry

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Signed-off-by: Adrian Catangiu <adrian@parity.io>
Co-authored-by: joe petrowski <25483142+joepetrowski@users.noreply.github.com>