feat: SPTool scaffolding

[magik6k]

Related Issues

This PR starts implementing #11733

Proposed Changes

• Setup the initial cmd structure
• Small abstraction for sharing of command code between SPTool and lotus-miner
• Bring over lotus-miner actor withdraw into the shared package

Additional Info

Not sure if we want to do this as one bigly PR bringing everything over at once, or if we want to land the almost empty binary first, then start bringing over more and more commands in smaller PRs.

I'm slightly leaning towards more smaller PRs, so this PR is ready for review as-is

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

[snadrus]

I've added actors.

[snadrus]

@magik6k It won't let me add you as a reviewer because I took it over from you.

[snadrus]

recreating this so Magik6k can review