Neo Express support

[devhawk]

Since it's a dev tool, neo express stores express wallet private key information without encryption. An Express Wallet adapter package would allow developers using the neo-wallet-adapter library to test their dApps locally with NeoExpress.

[mfbz]

Nice idea Harry! It would be really useful to connect locally 🤓

Basically we can add a "neo-express-adapter" that handle retrieval of the wallet by asking the user for wallet data and then uses neonjs do the calls to neo express on localhost directly signing the transaction with it.