Identification - E-Bill - Adapt CreateIdentity/Deanonymize

[zupzup]

• Switch to new API
• Clean up Identity Proof Stuff
• Once Backend/API part is done
  • Add challenge/register/confirm API and fields to CreateIdentity/Deanonymize
    • create Blocks
    • locally save mint signature (re-use identity proof stuff)
• Implement change email for Ident with challenge/register/confirm and creating Block