Add 2 new GraphicManager config entries GraphicMemoryLimit and
GraphicAllowedIdleTime. At the same time, deprecate the existing
config entries used in GraphicObject's GraphicManager, which are
not relevant anymore.

Change-Id: Idb775e5e1a623f6c23d0c67fea5334a6c713c6c2
Reviewed-on: https://gerrit.libreoffice.org/53561Tested-by: Jenkins <ci@libreoffice.org>
Reviewed-by: Tomaž Vajngerl <quikee@gmail.com>