Add a Kate setting to wrap plugin conf files to 78 columns.

Instead of 80, to fit nicely when indented with two spaces in
magnum-sceneconverter --info-converter and related options.

src/MagnumPlugins/.kateconfig

@@ -0,0 +1 @@
+kate-wildcard(*Importer.conf;*Converter.conf;*Font.conf): word-wrap-column 78;