Add a cli for ChangeBeneficiary

[jennijuju]

related #9253

I think for a better user experience, we should have to CLI

• lotus-miner actor propose-change-beneficiary
  • fail early if the caller is not the owner
  • should show if its a replacement of a pendingchange
  • we should handle the situation when the owner is a msig
• lotus-miner actor confirm-change-beneficiary
  • fail early if the caller is not the new beneficiary or the existing beneficiary
• we should create tooling for performing this action via msig (this can be a separate issue later)

[jennijuju]

@geoff-vball please review the scope and adjust the estimation accordingly (if we are doing msig in a later issue - then the estimation should go down to <8 imho)

[geoff-vball]

Msig tooling definitely shouldn't be in this ticket. I'd argue we might not want it at all? @arajasek

[arajasek]

Let's do both accounts and multisigs as part of this ticket. We just have to build off the existing change-worker functionality, which makes this very easy.

• That's 2 new commands in the lotus-miner CLI, following

  lotus/cmd/lotus-miner/actor.go

  Lines 47 to 48 in 15ea395

  	actorProposeChangeWorker,
  	actorConfirmChangeWorker,

• And 2 new commands in the lotus-shed -- following

  lotus/cmd/lotus-shed/miner-multisig.go

  Lines 33 to 34 in e65fae2

  	mmProposeChangeWorker,
  	mmConfirmChangeWorker,

[geoff-vball]

@arajasek I'm super duper confused at the workflow for actorProposeChangeWorker and actorConfirmChangeWorker. Propose sends a message signed by the owner key with a new worker address. Then Confirm sends a message with no params, also signed by the owner address. I don't understand the point of this. It would make sense to me that that message would be signed by the new worker address.