Add custom protocol config

[a-mpch]

In order to run LNDK along side my umbrel LND node I needed to modify manually the umbrel-lnd.conf to make it work (ssh into it and then modify it).

I would like to publish an app for LNDK to Umbrel but users would need to do some manual modification of their node or have a trigger button for it. Then, I thought adding these settings makes sense so their modification are only done through the same UI of their node and we could walkthrough them to it.

Then, this PR has 3 parts:

1. Updates the default development LND so we can make use of this apps.
2. Add support of the custom message and feature bits in the backend side. Handle the null value not writing it on disk.
3. Add the UI in the AdvancedSettingsModal that takes care of adding the configuration.

Happy to discuss if this approach makes sense.