Allow retrieving development accounts in useWallet() when connecting to a dev chain

[jimmychu0807]

Feature Request

Allow retrieving development accounts in useWallet() when connecting to a dev chain.

Motivation

It will ease the development effort as we often spin up a dev chain and writing the frontend to interact with the chain. But this is not a really high priority item as well, as we can always transfer some dev-chain tokens from dev accts (in say Polkadot-js Apps) to our actual wallet accounts for further transaction submissions.