Multi account support

[Oscar-Pepper]

pepper-sync will allow supporting multiple accounts but work will need to be done to support in zingo 2.0. supporting mulitple accounts will iikely be an important pre-req for many feature ideas in Chasqui. An example idea being that a "chatroom" wallet may create multiple "chats" (accounts) which each have its own UFVK to allow different sets of members for each account.