Trigger krunner using meta (windows) key

tested on kde 5.27:

Run these two commands:

kwriteconfig5 --file ~/.config/kwinrc --group ModifierOnlyShortcuts --key Meta "org.kde.kglobalaccel,/component/org_kde_krunner_desktop,org.kde.kglobalaccel.Component,invokeShortcut,_launch"

qdbus org.kde.KWin /KWin reconfigure