Update Architecture and Tests Documentations to Add the Agent Features and The cassandra-test-image

[VictorCavichioli]

Story Description:

The objective of this task is to update both the architecture and testing documentation to reflect the new functionalities implemented over the past month. This includes the introduction of the cassandra-test-image module, and the abstract Java class designed to manage these clusters during integration tests.

Acceptance Criteria:

[Acceptance Criterion 1]: The architecture documentation is updated to reflect the addition of the cassandra-test-image module and its role in creating a multi-datacenter Cassandra cluster for integration testing.

[Acceptance Criterion 2]: The testing documentation is updated to include instructions on how to set up, configure, and use the cassandra-test-image module, including the docker-compose.yml file and the abstract Java class using Testcontainers.

[Acceptance Criterion 3]: The documentation is reviewed for clarity and completeness to ensure that all team members can easily follow the updated processes.

Definition of Done:

Both the architecture and testing documentation are updated and fully describe the new cassandra-test-image module, Testcontainers integration, and abstract Java class.

Related to #652