Description of problem:
Inclusion of upstream commit link https://review.opendev.org/c/openstack/cinder/+/713710 along with some additional patches.

How reproducible:
Every time

Actual results:
Not able to set minimum/maximum volume size in any specific volume_type.

Expected results:
Ability to set minimum/maximum volume size in any specific volume_type.

Additional info:
With present commit, the minimum and/or maximum volume size 
for any specific `volume_type` can only be added/modified if there are no volumes present in it.
As soon as the volume will be created (irrespective of the size) within any `volume_type`, the property 'provisioning:min_vol_size'/'provisioning:max_vol_size' becomes immutable.

There is a requirement of this property to be editable even when volumes are present under `volume_type`.