GUI for Setup

@AnotherDroog is already working on this.

Since Oct 29, 2018.

We discussed the other night about creating a Web App GUI for making it easy to work with the box, including:

* A setup wizard for network configuration
* Bonjour discovery (xxx.local) for connecting
* The ability to create invoices and show the QR code
* Some kind of management console for funding, spending, opening channels, etc.
* (Possibly) A permissions system to manage multiple devices creating invoices and spending

Luckily, it looks like LND supports GRPC out of the box, so as far as I can tell, it'll enable us to do HTTP calls directly from clients in a web app (no special middleware required). We could bundle a a static HTML/JS app with very little overhead (served on the device via local network and/or tor) which could talk directly to the LND node, or through a reverse proxy on the box.

The main issues we face are regards to security. We need to think about how the bootstrap process can be secured, followed by general use (perhaps some kind of secure token is stored on the clients, so we don't need to rely on HTTPS, which won't work with .local, and/or a protocol such as [SRP](https://security.stackexchange.com/a/48619)), as well as system reset / key recovery (it was mentioned that we could use a seed to generate creds for both the node and this system).

I expressed interested in helping with the development of this, including playing with the recently released [blueprint](https://blueprintjs.com/) framework.

Ref:
https://api.lightning.community/
https://github.com/lightningnetwork/lnd/tree/master/lnrpc
https://grpc.io/