[WIP] Trezor large transactions draft

[gabrielKerekes]

If you want to test signing a large transaction you can do so by following these steps (if you know of an easier way, please let me know :wink:):

1. Download and run this gist in the cardano-hw-cli root. This will create a script to generate 300 key files in a keys subfolder which needs to be created.
2. Run the gen_keys.sh script.
3. Download and run this gist in the keys subfolder. This will create a script to generate a transaction with 300 inputs. Make sure to replace [PATH TO CARDANO-CLI] with the path to cardano-cli.
4. Download and run this gist in the cardano-hw-cli root. This should try to sign the raw transaction created in the previous step. Without these changes this should fail due to an issue with the cbor library.