Add keyspace field in audit log

[laxmikant99]

We currently don't have ks field. To make it compatible with 4.0, we should have it.

[eperott]

Nice proposal! Should be pretty straight forward to implement this. However, this is probably no small task.

Would be nice if we could get a behavior which is identical to that of audit logger in Cassandra 4.0.

I'm thinking that either we use the existing AuditEntry.getResource(), or we create a specific field for the keyspace in AuditEntry and populate it from AuditEntryBuilderFactory.

Then we should add support for this field in both SLF4J logger and Chronicle logger (including eclog tool).