fdo#68849: Add header guards to all include files

Added header guards to files in directories desktop/*, and embedserv/*

Change-Id: Idaffcc0539b84962ed7c132cb20078512799d433
Reviewed-on: https://gerrit.libreoffice.org/9556
Reviewed-by: Noel Grandin <noelgrandin@gmail.com>
Tested-by: Noel Grandin <noelgrandin@gmail.com>