Add filter-based deletion to Cassandra Vector Store

[sobychacko]

Implement filter-based deletion for CassandraVectorStore to support more
flexible document removal based on metadata filters.

Key changes:

- Add doDelete(Filter.Expression) implementation
- Implement workaround for Cassandra's limitations in direct filtered deletion
- Fetch matching documents first, then delete by IDs
- Add integration tests for various filter deletion scenarios
- Support simple and complex filter expressions
- Includes tests for:
  * Deleting by simple equality filter
  * Deleting by string-based filter expression * Deleting by complex AND filter expression

Provides consistent deletion capabilities across vector store implementations while addressing Cassandra-specific constraints.