qa/tasks: tests for resize subvolume

qa/tasks: tests for resize subvolume

* That a subvolume can be expanded in size and its quota matches the expected size.
* That a subvolume can be shrinked in size and its quota matches the expected size.
* That a subvolume cannot be resized to an invalid size and the quota did not change
* That a subvolume cannot be resized to a zero size and the quota did not change
* That a subvolume can be resized to a size smaller than the current used size and
  the resulting quota matches the expected size.
* That a subvolume cannot be resized to a size smaller than the current used size when
  --no_shrink is given and the quota did not change.
* That the subvolume can be expanded from a full subvolume and future writes succeed.

Fixes: https://tracker.ceph.com/issues/41182
Signed-off-by: Jos Collin <jcollin@redhat.com>