Improve Trezor Integration & Support

[OBorce]

Features:

• Add support for signing with standalone private keys.
• Allow users to select a specific Trezor device when multiple devices are connected simultaneously
  • in wallet-cli;
  • in node-gui.
• Support entering the Trezor passphrase directly from the wallet GUI/CLI.

Improvements:

• Improve handling of communication timeouts if the user doesn't perform the action on the device within 100s
  (Edit: this may not be relevant anymore, but more testing is needed)

CI:

• Implement automated tests for Trezor support using the Trezor Emulator and integrate them into the CI pipeline.