Update name & id of appstream metainfo.xml file
New naming pattern "org.kde.kio.worker." following here existing examples like "org.kde.plasma.", "org.kde.discover.", "org.gnome.Software.Plugin.". At least personally favour such strong namespacing patterns :)
New name of screenshot "kio-zeroconf" on https://invent.kde.org/websites/product-screenshots yet needs to be created, would do once this is approved by copying the "zeroconf-ioslave" one over (still needs to stay for a while as existing instances will refer to it. Not sure if this should also match the appstream id instead, or if following the more common non-namespaced name (in this case matching the repo name) is fine. For consistency with existing screenshots I proposed the simple name here.