nymea-plugins pull request checklist:

* Make sure the pull request's title is of format "Plugin name: Add support for xyz" or "New plugin: Plugin name"

* Did you test the changes on hardware, if not (e.g. absence of required hardware), please mention a person to confirm it has been tested.

* Did you update the plugin's README.md accordingly?

* Did you update translations (`cd builddir && make lupdate`)?

* If you added a new plugin, should it be added to nymea-plugins-all or nymea-plugins-maker?