As reported in the bug ticket, the commands SID_ZOOM_IN and SID_ZOOM_OUT are not smooth and increase/decrease zoom at too big steps.
This patch uses basegfx::zoomtools to zoom in and out, making it smoother.
Change-Id: I801fa6123bf0696046e5d45c7a6b309e7cc3312e
Reviewed-on: https://gerrit.libreoffice.org/c/core/+/146825
Tested-by: Jenkins
Reviewed-by: Jim Raykowski <raykowj@gmail.com>