Support GRPC over Tor.

[Kixunil]

Is your feature request related to a problem? Please describe.
The wallet currently uses different QR codes for Android and iOS, which leads to UX issues and developer churn. The user needs to know what platform and protocol is being used and select it when generating QR code, the developer must know about this (poorly documented) limitation implement it and test it.

Describe the solution you'd like
Just support GRPC everywhere.

Describe alternatives you've considered

• Supporting REST everywhere instead could be an option but GRPC is more efficient so should be the best. It'd also require migrating GRPC clients.
• Supporting both with auto-detection would be nice but perhaps too complicated?
• Keeping sad UX as is - that'd be a real shame as Zap is great otherwise.
• If this is too complicated, the lndconnect link could be extended to specify both GRPC and REST. Then Zap could just use the relevant protocol.

Additional context
Yeah, I've just spent around an hour on solving this and in parallel was designing some GUI around QR code which now needs to be redesigned unless this is resolved.