Add protocol handlers for PWA

[benthecarman]

Looks like we can have it so when we scan a QR outside the app, mutiny will be an option.

Should hook this up for lightning, bitcoin, and lnurlp

https://developer.mozilla.org/en-US/docs/Web/Manifest/protocol_handlers

[benthecarman]

I think to do this we need to be able to do something like /send?param=somestring so we can load it that way

[TonyGiorgio]

This would only be useful for chrome on android from what it looks like.