Consider hardware wallets in register command

[strophy]

It would be great to still be able to use the register command when setting up mainnet (and testnet) masternodes with the collateral held on hardware wallets. In this case, it is not possible (or strongly not recommended) to export private keys from the hardware device. In this case, the register command will need some adjustment and interactive prompts to handle typical workflows for registering masternodes from hardware wallets. We also need to think about if and how DMT can play a role, or if we should document two separate approaches to hardware wallet collaterals.

Expected Behavior

It is possible to register a masternode using mn-bootstrap with the collateral held on a hardware wallet without exporting the funding private key.

Current Behavior

Private keys are required

Possible Solution

Interactive prompts, or different "modes" to the register command

Alternatives Considered

Some sort of tango involving copying transactions back and forth between DMT/Dash Core?

[shumkov]

Partially it's already implemented but we still rely on Core or DMT to register a masternode so I keep this issue open.