Create helm charts for a clustered implementation of Cassandra.

Acceptance Criteria:

• data is persisted when db goes down via PVC/PV

• db nodes able to restart without losing stable data

• appropriate security

• image source is trusted

• table initialization appropriate for shared use

• logs integrated into ONAP logging

• automatic leader election

• able to dynamically add cluster members

• able to dynamically remove cluster members

• appropriate load balancing of external requests

Sub-tasks track migration of existing project implementations to these common charts.