utils: Add support for svg cursors
With this change, KXcursorTheme will be able to load svg cursors provided by breeze.
If a cursor theme provides both xcursor cursors and svg cursors, the svg cursors will be preferred.
At the moment, KXcursorTheme doesn't cache svg render results but it could do that if it becomes a noticeable issue.
Edited by Vlad Zahorodnii