Add HTTPS server

[misku]

Configuration example:

"http_server": {
  "type": "https",
  "port": 8891,
  "cert": "/path/to/fullchain.pem",
  "key": "/path/to/privkey.pem"
}

type: "http" | "https" (default: "http")
port: (default 8282)
cert: path to server certificate
key : path to private key

If "http_server" key is missing, no HTTP server will be started.
If "type" == "https" && ("cert" || "key" is missing or corrupted)
an error will be thrown.

[maddox]

This is great, thanks! Just a couple of notes.

1. Could you make it so enableHTTPserver still enables the http server. Otherwise it will break current installs after an upgrade. This is an easy way to keep some backwards compat.
2. Could you document this in the README.

[misku]

Sure, no problem. I'm glad you like it.