Split AstraDB and Cassandra Stores

[clun]

Context

AstraDB expose a mongo-like api different from the low level CQL (Cassandra Query Language). It is still possible to use the CassandraEmbeddingStore but the Astra DB layer offer richer filters capabilities matchin criteria from langchain4j.

Change

Split Cassandra and AstraDB, implementing now AstraDB Store, Adding more tests.

Checklist

Before submitting this PR, please check the following points:

• I have added unit and integration tests for my change
• All unit and integration tests in the module I have added/changed are green
• All unit and integration tests in the core and main modules are green
• I have added/updated the documentation
• I have added an example in the examples repo (only for "big" features) You can find the associate PR HERE
• I have added my new module in the BOM (only when a new module is added)

Checklist for adding new embedding store integration

• I have added a {NameOfIntegration}EmbeddingStoreIT that extends from either EmbeddingStoreIT or EmbeddingStoreWithFilteringIT