chore: Move Linux-only configs out of "common" and into "linux"

common/.config/kate/externaltools/Search%20Qt%20API.ini

@@ -1,12 +0,0 @@
-[General]
-actionName=externaltool_QtAPI
-arguments="https://doc.qt.io/qt-5/search-results.html?q=%{Document:Selection:Text}"
-category=Tools
-executable=xdg-open
-icon=qtcreator
-name=Search Qt API
-output=Ignore
-reload=false
-save=None
-trigger=None
-workingDir=%{Document:Path}