Overview:
As a tester, I need to verify the sanity of Cassandra pod.
Write test cases as healthchecks to verify sanity and health of Cassandra:
1. Connect to each Cassandra replica pod and login to cqlsh and read a value in a table. Validate that you are able to read a value.

Fail the test case for the following:  a. failed to connect to the Cassandra pod b. failed to login to cqlsh c. failed to read a value from a table in CQL database

2. Some environments have different number of Cassandra replicas. Typically 3 replicas or only 1 replica.
    As a tester, i want to verify the number of Cassandra replica pods that are "running" state vs. the number of Cassandra replica of stateful set.
    if the number of replicas "running" is less that the value in stateful set, AND if there is a replica that is being initiated or rebooted, 

then our test case can wait for 60 seconds and check the number of "running" replicas again and validate.  The reason is sometimes 1 replica would crash and reboot, and recovers on its own. The time for the pod to go down and come back up is 60 seconds.  We can pass the test case if we waited for 60 seconds and the pod comes back up "running".

Acceptance Criteria:

• 2x healthchecks are implemented to validate Cassandra