Optimize Docker usage by enabling container reuse

[akoumany]

Why are these changes needed?

These changes aim to enhance the efficiency of the DockerCommandLineCodeExecutor by allowing it to reuse existing Docker containers instead of starting a new one for each code execution.

This approach not only speeds up the code execution process by reducing the overhead associated with container setup and teardown but also aligns with sustainable resource usage practices.

Although these changes do not fully resolve #741, they incorporate the suggestion from bbence84 on the potential performance improvements from reusing containers.

Related issue number

Partially addresses #741 and somewhat related to #929

Checks

• I've included any doc changes needed for https://microsoft.github.io/autogen/. See https://microsoft.github.io/autogen/docs/Contribute#documentation to build and test documentation locally.
• I've added tests (if relevant) corresponding to the changes introduced in this PR.
• I've made sure all auto checks have passed.

[akoumany]

@microsoft-github-policy-service agree