Edit ledger and balance details

[stkegoul]

Is your feature request related to a problem? Please describe.
When I create a new ledger or balance, I can sometimes make mistakes or leave out some attributes or have incomplete metadata to be completed at a later time.

Describe the solution you'd like
I want to be able to:

1. Update my ledger details, e.g., name.
2. Update my balance details, e.g., add an identity_id to an already created balance.

Describe alternatives you've considered

• I create a new one with the new details I want it to have.
• No alternative for updating identity_id in my balance.

Additional context
#52 covers my request to also be able to update meta_data