fdo#68849: Add header guards to all include files

Added header guards to directory filter/
Fixed missing INCLUDED_ prefix

Change-Id: I091e6a0262d3a58b3b784e39970f79c5b10d04f5
Reviewed-on: https://gerrit.libreoffice.org/9521
Reviewed-by: Thomas Arnhold <thomas@arnhold.org>
Tested-by: Thomas Arnhold <thomas@arnhold.org>