QR Server

Listen on a port and serve QR codes encoding data from the path or the
request body.

For example, if running on localhost and port 5000, then both of the
following are supported ways to generate a QR code encoding the string
"hello-there":

- curl http://localhost:5000/hello-there
- curl -d 'hello-there' http://localhost:5000

If the path following the hostname is non-empty, that will be used as the
data to encode, and the request body will be ignored.

By default, listens on port 5000. To listen on another port, use sudo snap set qr-server port=<port>, with <port> being any available
port number.

Both GET and POST requests are accepted and may be used interchangeably.