LedgerCommand and State should not rely on common::DisplayAddress

[edouardparis]

LedgerCommand should satisfy the ledger api. Having it nested enum variants that are not part of this api like
common::DisplayAddress::ByMultisig is a nonsense.

We should have a dedicated struct in the Ledger module with only the variants that will be consumed by the device api.

Device commands should never rely on common struct. We want to keep the scope of each device module focus on their devices.
Maybe we should move also every DeviceCommand -> common::Command, DeviceTransmit -> common::Transmit etc to the common module. to discuss.

[trevarj]

Yes, agree, this needs to be refactored. Might also need to be
refactored on other devices, but I didn't look yet.

Not sure about moving the [Device]Commands to common though. I will
have to think about that.