Add an ability to choose derivation path on Ledger connect

[clicman]

For example to choose between [44, 474, 0, 0, i] and [44, 474, i] and maybe another options

[matevz]

Hey @clicman,

there's a PR for the web wallet which enables this #761, but we decided not to merge it until we implement some advanced switch. The wallet should be idiot-proof across the Oasis ecosystem and users will get confused, if there will be two derivation paths suddenly available - one of them not supported by the older versions of the wallet. If you want to use Ledger with the derivation path defined in ADR-8 ([44, 474, i]), use Oasis CLI for now.

[matevz]

Closing - duplicate of #760 .