Pull out offline transaction and account creation from algonaut into wallet-usable codebase

[longtomjr]

The goal here is to take the functionality that we need from Algonaut into a codebase that is either no-std compatible, or only use the Teaclave rust sdk's std library (with no-std being preferred if possible).

The functionality that we need is:

• [x] Create account (api docs|source)
• [x] Create and sign a transaction (several steps) { note: initially just try and implement it using the types, we can do the builders in the future if needed }
  • [x] Create the payment (api docs|source)
  • [x] Create Transaction - for now we only need "payment" transaction types. (api docs|source)
  • [x] Sign transaction using the sender's account (api docs|source)

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Repo: https://github.com/registreerocks/algonaut-sgx

[PiDelport]

We pulled this into an SGX-forked crate: https://github.com/registreerocks/algonaut-sgx