Settings component that allows customising RPC/API endpoints, etc.

[faddat]

Select the RPC node:

I reckon:

For now we give this the sanest default possible and provide a place for the user to enter the URL. Will work nicely with new GH pages auto-deploy.

User can have a pi at splash.local, enter splash.local and their browser will access that rpc from github pages.

Pattern also allows for mass experimentation with front ends.