don't write extension elements into ODF namespaces, related fdo#45266

We will still import the old elements but only write them into the
lo-ext namespace. Also it will only be exported for ODF 1.2 extended.

(cherry picked from commit 88d3931d92bc89519acf95f0510f6f2a6ff7c72c)
Signed-off-by: Michael Stahl <mstahl@redhat.com>

Backpoting the export part of this too since the attributes were added
in LO 4.3 so the change has very limited impact.

Conflicts:
	xmloff/source/chart/PropertyMap.hxx

Change-Id: I1c41716b8b16e186ec84767b4b3a636d083162b8