Convert MD_ICONSELECTOR and MD_ICONCHANGE to .ui

I implemented multiple row ToolBox in MD_ICONSELECTOR.

Change-Id: I0f275b2332a15f3ba37952f6a104099e4f1f1678
Reviewed-on: https://gerrit.libreoffice.org/10112
Reviewed-by: Caolán McNamara <caolanm@redhat.com>
Tested-by: Caolán McNamara <caolanm@redhat.com>