This change makes LXQt use the Breeze icon theme, and adds it as a
desktop environment along the other supported DEs.

Change-Id: I482d85620986c8fc4e33b4722b887b81c77c23bf
Reviewed-on: https://gerrit.libreoffice.org/61641Reviewed-by: Samuel Mehrbrodt <Samuel.Mehrbrodt@cib.de>
Tested-by: Samuel Mehrbrodt <Samuel.Mehrbrodt@cib.de>