Proposal: Usage of `ledger-thorchain-js`

[veado]

ledger-thorchain-js will be the "official" JS Ledger library for THORChain. Since hdwallet is already using @ledgerhq/hw-app-btc and @ledgerhq/hw-app-eth, ledger-thorchain-js might be a good option as well.

[mrnerdhair]

Thanks for opening this issue -- I know we talked in Discord but this definitely helps track things better. I expect we'll be looking to add support for the THORChain Ledger app soon, and this may be the best way.