Add support for docker network for reuse

[morazow]

Situation

Testcontainers reuse mechanism does not work if the container is attached to a network. See: https://github.com/testcontainers/testcontainers-java/pull/1781 (Challenges Ahead).

For time being we can support a named docker network from the exasol-testcontainers. We already have two projects that use Exasol containers with networks.

Acceptance Criteria

• Named docker network class is added (from DockerNamedNetwork)
• Unit and integration tests are added

[redcatbear]

No capacity.