Mita should have a Hono system resource

[csweichel]

At the moment Mita stands a bit removed from the other Eclipse IoT projects. As a first means of integration, a Hono system resource looks like a good choice.

Eclipse Hono provides uniform device access to IoT applications. Because Hono can be connected to using MQTT, implementing a Hono adapter for the XDK110 platform is a low hanging fruit.

Using the Hono resource, users would be able to write

package main;
import platforms.xdk110;

setup wlan: WLAN {
    authentification = Personal(psk="password");
    ssid = "NetworkName";
}

setup backend: Hono {
    transport = wlan;
    url = "mqtt://hono-mqtt-adapter.com";
        authentication = Unauthenticated(tenant="foo", deviceId="bar");
        // authentication = Authenticated(username="sensor1@tenant", password="bar");
       var evt = events();
}

every 1 second {
        backend.evt.write(`{ "temp": ${environment.temperature.read()} }`);
}

[sophokles73]

This would be really great to have so that we can easily use the XDK for showcasing end-to-end device integration with Hono and Ditto :+1: The same pattern could be used for Hono's HTTP adapter as well, I guess. The particular endpoint addresses are documented in the HTTP and MQTT Adapter's User Guide.

For sending Telemetry, the QoS level to use can also be set for each message separately, so that should also be configurable.