[Feature] Add `-finalize-early` flag

[jcace]

• with the max_concurrent value, it would be good to conditionally exclude any sectors that are in Sealer: SubmitCommitAggregate

• If --finalize-early is TRUE, then we can exclude them. Otherwise, include them in the count

• Provide documentation - this flag should match the user's configuration on lotus-miner.

• If true, lotus-miner will move the sector to long-term storage before the final commit on-chain. Thus, the sector is moved off the sealing server and does not "take up space" in the sealing pipeline, so it can be ignored by the max_concurrent logic in DI.

[jcace]

I think it's a good idea to finish #23 first