Refactor/use new register method

[devceline]

Note

All required PRs have been merged.

Changes

Per new spec updates here, here , here, and identity util changes here, the notify client registration methodology is as follows:

• register is now split into two functions :
  • prepareRegistration: Actually prepare the registration
  • register: Use the prepared registration, as well as a signature of the message from prepped registration, to actually register the identity.
• Addition of new function isRegistered to check registration status.
• Update checkStatementIsStale to checkRegistrationIsStale since it now also checks against domain.

Implications of this

• Register now no longer automatically unregisters accounts that have stale statements. That logic is now handled by the user of the client, via checking isRegistered.
• UIs (I.E Web3Inbox) will have to refactor how they handle signatures completely

Tested

Tested via updating existing unit tests to use new API.

Notes

• Won't merge until Make isRegistered take same params as prepareRegistration to check registration status accurately walletconnect-specs#181 is merged
• Identity keys 1.0.1 is currenty a canary, will go to stable once this is merged.

[bkrem]

🚀 🚀

Great PR description here 🔥

[bkrem]

Not a huge fan of this boolean naming but I see it's been agreed in the spec for the parameter further up so fine with keeping this consistent