Add termination-estimate to get an estimation for how much a termination penalty will be

[jennijuju]

• Usage example: ./lotus-shed sectors termation-estimate 5 8 10.

Resolves #4616

[arajasek]

It'd be great if you could add the "detect pending terminations" function @Stebalien discussed. It would probably need adding a new method to chain/actors/builtin/miner/miner.go, and its implementations.

If not, throw a TODO in the code and merge this, it's only going into shed.

[jennijuju]

@Stebalien @arajasek thanks for the feedbacks! after talking to Steve, i think we can merge this one as it is as a very rough estimation, and then im gonna create another ticket to implement the more accurate option(sweep back the tipset until pending termination is 0) .

[arajasek]

@jennijuju That's fine, but do add a TODO in the code summarising the discussion here.

[jennijuju]

@jennijuju That's fine, but do add a TODO in the code summarising the discussion here.

added

[magik6k]

ok for first impl