Enable modifying Block Issuer Keys in CLI Wallet

[PhilippGackstatter]

Description of change

Enable modifying Block Issuer Keys in CLI Wallet. This is so prospect validators can easily add a second dedicated block issuer key for use in inx-validator. It needs the private key corresponding to the block issuer key in order to be able to issue validation blocks. Since the private key of the block issuer key added by the sdk is in stronghold or the ledger and thus not extractable, a new command was necessary to be able to add external block issuer keys.

Links to any relevant issues

n/a

Type of change

• Enhancement (a non-breaking change which adds functionality)

How the change has been tested

Manual local testing with the cli.

Change checklist

Tick the boxes that are relevant to your changes, and delete any items that are not.

• I have followed the contribution guidelines for this project
• I have performed a self-review of my own code
• I have commented my code, particularly in hard-to-understand areas
• I have made corresponding changes to the documentation
• I have added tests that prove my fix is effective or that my feature works
• I have checked that new and existing unit tests pass locally with my changes

[thibault-martinez]

I reopened a comment just to be sure, resolve again if you want