Saves the recently executed UNO commands in a temp file and make it
accessible to user in a combo box. Useful when debugging.

Change-Id: Ic66961a388cc59dee3f65cb8d4de3c29a8a75eaa
Reviewed-on: https://gerrit.libreoffice.org/45540Tested-by: Jenkins <ci@libreoffice.org>
Reviewed-by: pranavk <pranavk@collabora.co.uk>