openHAB integration without "View the map"-workaround

[ingoschi]

I found a way to do the openHAB integration much easier without any "View the map"-workaround.

I changed my ICantBelieveItsNotValetudo implementation to optionally publish the map as base64-encoded string to
MQTT 'MapData/map' instead of the png image.
I didn't want to use an additional topic, because Valetudo only registers 'MapData/map' for Homie autodiscovery.

Now I can add in openHAB for my vacuum thing the Map channel and create an image type item, and the image will directly update when ICantBelieveItsNotValetudo draws and publishes a new map to MQTT.

In openHAB event.log will only occur one row:
2021-10-17 22:22:46.163 [INFO ] [openhab.event.ItemStateChangedEvent ] - Item 'DreameD9_Map' changed from raw type (image/png): 10007 bytes to raw type (image/png): 9843 bytes

There will be no change needed in Valetudo (besides the openhab integration documentation)
and ICantBelieveItsNotValetudo would get an option mqtt.publishAsBase64 with default false.

[ingoschi]

The option mqtt.publishAsBase64 is now added to ICantBelieveItsNotValetudo.
Hypfer/ICantBelieveItsNotValetudo@0626ff5

I'll do a PR for the change of openhab integration documentation later tonight.