Support volume local cache
Support volume local cache

Add the support of cache software that caches remote slow volume using
fast local SSD or persistent memory.

Related Nova spec:
https://review.opendev.org/#/c/689070/

Change-Id: I4d6e44789ece9accda2044dbf31bbf8f8393fbd2
Signed-off-by: Liang Fang <8038842c8bcaaa6f2e8a646abff91be1f359b5e0@intel.com>

openstack/cinder-specs