Runtime: add support for substrate generic ledger app

[mochet]

Problem

We don't have support for the Generic Ledger app (for the hardware wallet) in our runtime. It looks like the code for doing this will be available relatively soon. This is an item that is on our roadmap.

Solution

https://x.com/bkchr/status/1797987390067548233?t=ONWtO61cn6vK8uMOq4SFmg
Generic Ledger app support is getting added to Polkadot very soon and it looks like the audit of the app itself will be done towards the end of June.

[bedeho]

Very exciting, seems like this should be in the next runtime upgrade after Petra perhaps?