Associating an existing ID with another keypair (CryptoUpdate)

### Problem

Associating an existing ID with another keypair.

Use Case: I want to keep my ID that is tied to a software keypair and move it to a secure Ledger hardware wallet keypair.

### Solution

Implement [this feature](https://docs.hedera.com/guides/docs/hedera-api/cryptocurrency-accounts/cryptoupdate).

### Alternatives

There is no wallet that supports this feature yet so I used [BugBytes tool](https://hashgraph.bugbytes.com/updateaccount). The problem is that their [signing tool](https://www.microsoft.com/en-us/p/hashgraph-signing-tool/9ppb258cd9p7) does not support communicating with a Ledger hardware wallet. I have to paste in the private keys of both participants.