feat: Add ETA to lotus sync wait

[fridrik01]

Related Issues

none

Proposed Changes

This PR adds a ETA indicator to lotus sync wait command which I felt was missing when waiting for my node to finish syncing

Additional Info

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
• 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

[Stebalien]

Looks reasonable, although see my comment.

[Stebalien]

"It works". It could probably use some more smoothing (e.g., a longer history), but it works and we can improve it later if we get complaints.