feat: lotus-provider: Storage reservations in SDR

[magik6k]

Related Issues

This PR addresses one of the remaining items from #11534

Proposed Changes

• Add a mechanism to CanAccept which makes it possible to reserve a resource which will be freed if task isn't taken, or will get passed to Do if it is.
• Use this mechanism to implement early storage reservation in the SDR task

Additional Info

I did some manual testing on mainnet, and it seems to work flawlessly.

• Started a batch of 12 sectors with one SDR node which is only able to take 8
• Because the machine has multiple drives the initial batch didn't get space all at once
• Second run of CanAccept succeed for more sectors on the other drive
• Now it's just calmly waiting for more storage to become available
• At no point has the task registered an error, because it never errored!

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
• If the PR affects users (e.g., new feature, bug fix, system requirements change), update the CHANGELOG.md and add details to the UNRELEASED section.
• New features have usage guidelines and / or documentation updates in
  • Lotus Documentation
  • Discussion Tutorials
• Tests exist for new functionality or change in behavior
• CI is green

[magik6k]

Closing in favor of #11647