mTLS Support for Cassandra Cluster Connectivity

[bradfordcp]

Is your feature request related to a problem? Please describe.
I'm looking to connect to a Cassandra cluster with mTLS. This requires an SSL certificate to be presented from the client-side.

Describe the solution you'd like
I would like to be able to specify paths to x509 encoded certificate and key files. The Cassandra client should use these files as part of its SSL configuration when communicating with the cluster.

Describe alternatives you've considered
A sidecar for adding the SSL encryption, but this seems a bit ridiculous given the driver supports this configuration.

Additional context
Sample logic showing how it is implemented - https://github.com/flightc/astra_gocql_connect/blob/master/astra_gocql_connect.go