Re-incorporate parts from the Wallet SDK

[arboleya]

There is a refactoring going on the fuels-wallet repo regarding the SDK package:

• https://github.com/FuelLabs/fuels-wallet/tree/sdk-v2/packages/sdk

The idea of the issue is to re-incorporate that part in this repo for a better separation of concerns.

It's part of a bigger RFC that @luizstacio started here:

• https://github.com/FuelLabs/fuels-wallet/wiki/Fuel-Wallet-Connectors

#1518 should super-cede this task by first restructuring the Account package to then incorporate the above repo.

Note

• Incoming from Feedback - Frontend #1537