Add Cassandra session level tracking

[Claude-at-Instaclustr]

PR #598 (Use cql3 parser) brings with it the ability to process non-SQL commands.

One of the commands USE <keyspace> changes the state of the connection on the server side. In order for Shotover to properly process commands after the USE command it must track the keyspace named in the command and apply it to parsed names where the keyspace is permitted but not provided. Effectively, the USE command sets a default keyspace.

This change should figure out how to track sessions (not requests) between the client and the server so that the default namespace, and similar values, can be tracked across the requests. The session ID may be different from the stream ID found in the Cassandra frame itself. Part of this issue is to determine if that is the case or not.

The end result is that we will have the ability to store and clear session data so that data that crosses requests can be handled efficiently and consistently across the code base.

[rukai]

we ended up taking a somewhat different approach but the proper handling of use statements was implemented by #806