fdo#80894 : Rotation value for textframe was missing after RT.

   - Rotation property is not available for TextFrame in LO.
   - Hence grabbaged this value.
   - Roundtripped rotation value by converting it properly for both dml and vml textbox.
   - Added UT for it.

Change-Id: Ia040d55dc2ea79500df76877ba44a02971c872a8
Reviewed-on: https://gerrit.libreoffice.org/10190
Reviewed-by: Miklos Vajna <vmiklos@collabora.co.uk>
Tested-by: Miklos Vajna <vmiklos@collabora.co.uk>