feat: vm: allow raw "cbor" in state and use the new go-multicodec

[Stebalien]

Proposed Changes

1. Switch to go-multicodec as the source of multicodec code information. This gives us a central, generated source of multicodec codes.
2. Use this library inside the VM and shapshot logic to consistently allow CBOR, in addition to DagCBOR.
3. Remove the hard-coded CBOR constant.

This doesn't add any functionality in practice, it's just a post FEVM cleanup.

Checklist

Before you mark the PR ready for review, please make sure that:

• Commits have a clear commit message.
• PR title is in the form of of <PR type>: <area>: <change being made>
  • example: fix: mempool: Introduce a cache for valid signatures
  • PR type: fix, feat, build, chore, ci, docs, perf, refactor, revert, style, test
  • area, e.g. api, chain, state, market, mempool, multisig, networking, paych, proving, sealing, wallet, deps
• Tests exist for new functionality or change in behavior
• CI is green

[arajasek]

LGTM, gonna see if we can test out the snapshot changes somehow as part of our effort to test PRs more rigorously before landing.

[Stebalien]

I've tested this on calibnet and snapshots appear to round-trip. I.e.:

1. Import snapshot.
2. Export snapshot at the same height.
3. Check hashes and they matched.