feat(cspi status): add provisioned and healthy replica count in CSPI status

[mittachaitu]

This PR adds Provisioned and Healthy
replica count in CSPI status.

• When users execute kubectl get cspi -n openebs below will be output

 kubectl get cspi -n openebs
NAME                HOSTNAME    ALLOCATED   FREE     CAPACITY    READONLY   PROVISIONEDREPLICAS   HEALTHYREPLICAS   STATUS   AGE
cstor-stripe-fb4b   127.0.0.1   190k        19200M   19200190k   false      2                     1                 ONLINE   36m

Provisioned Replicas: Count of volume replicas present in the pool.
Healthy Replicas: Count of Healthy volume replicas present in the pool.

It will be helpful to users to know how many replicas are healthy out of provisioned replicas
without executing kubectl get cvr -n openebs -l cstorpoolinstance.openebs.io/name=<cspi_name>

Note to reviewers:

• Fetching information of Provisioned Replicas from zfs list and Healthy replicas using zfs stats.

Signed-off-by: mittachaitu sai.chaithanya@mayadata.io

[shubham14bajpai]

LGTM