feat: worker: Add stop cmd for lotus worker

[shrenujbansal]

Related Issues

#5227

Proposed Changes

Adding cmd to stop lotus worker similar to existing processes

Additional Info

Checklist

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

• 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
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• 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

[magik6k]

Thanks for the PR!

Needs running make gen to generate some missing docs.

[magik6k]

Thanks for the PR!