profilesafe: added xml read/modify to restore

To be able to restore the last saved state of enabled/disabled
extensions it is necessary in SafeMode to get and set that states
without XExtensionManager, so the configuration xml files have
to be accessed. Added this change

Change-Id: I00fe5795598427e7c08be0d3dd54bef68d038e24
Reviewed-on: https://gerrit.libreoffice.org/30062Tested-by: Jenkins <ci@libreoffice.org>
Reviewed-by: Armin Le Grand <Armin.Le.Grand@cib.de>