When we want a different size Image, we can now set that as a
parameter at construction of the Image. Previously we needed to
create an Image, forcefully take the bitmap out, resize the bitmap
and create a new Image out of that.
Doing it internally gives us the benefit to have a more control
over the scaling process, especially when dealing with HiDPI
images.

Change-Id: I104118f4d863d519cc7aad1a17ca0289c01ed9ff
Reviewed-on: https://gerrit.libreoffice.org/70617
Tested-by: Jenkins
Reviewed-by: Tomaž Vajngerl <quikee@gmail.com>