feat: add API methods to get allocations and claims

[geoff-vball]

Related Issues

Integrates filecoin-project/go-state-types#88 into lotus

Proposed Changes

Adds 3 new API methods:
Add StateGetAllocations to return a map of all allocations for a given client.
Add StateGetClaims to return a map of all claims for a given provider.
Add StateGetClaim to return a claim given a provider and ClaimId

Additional Info

Checklist

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• All commits have a clear commit message.
• The 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, INTERFACE BREAKING CHANGE, CONSENSUS BREAKING, build, chore, ci, docs,perf, refactor, revert, style, test
  • area: api, chain, state, vm, data transfer, market, mempool, message, block production, multisig, networking, paychan, proving, sealing, wallet, deps
• This PR has tests for new functionality or change in behaviour
• If new user-facing features are introduced, clear usage guidelines and / or documentation updates should be included in https://lotus.filecoin.io or Discussion Tutorials.
• CI is green

[geoff-vball]

The API methods for StateGetClaim and StateGetAllocation aren't strictly necessary. We could always return the map and let the client access the ID they want themselves, but would be a fair bit less efficient.

[jennijuju]

@arajasek @geoff-vball can you help me understand why this got prioritized? i.e: does this make further changes easier later? I want to understand if this is needed for development, why we did not capture it in the initial issue creation.

[geoff-vball]

@jennijuju StateGetAllocation was necessary for dealpacking (it's already included in the big PR). These were very quick and easy to add after that and allow us to test the new verifreg functionality if we want.

[jennijuju]

nice!