Ability to create signs

[maektwain]

This will ensure that injected or whatever is available creates the signature that we store so that we can remember the wallet entry.

Maybe check BIP33 Implementation

This will be stored in local cache or storage of sort in the browser that will have like _addressSignature, this will be generated by calling a method once the user is logged in with wallet,

createSignature()
store()

[pulkitvyas08]

There is a function with message signing in #5 that is currently unused so I'll see if I can repurpose that for this issue