Enable composite compose

[farbod-farshidian]

Description

This PR updates the container.sh script to support the creation of composite Compose files. By allowing external docker-compose and environment files to be provided to the Compose command, users can utilize both the Merge and Extend strategies.

Example for Merge: Users can supply a new .env file to override the DOCKER_ISAACLAB_PATH variable in the base Docker configuration.
Example for Extend: Users can provide external docker-compose and env files to extend the base service.

Type of change

• New feature (non-breaking change which adds functionality)

Checklist

• I have run the pre-commit checks with ./isaaclab.sh --format
• I have made corresponding changes to the documentation
• My changes generate no new warnings
• I have added tests that prove my fix is effective or that my feature works
• I have run all the tests with ./isaaclab.sh --test and they pass
• I have updated the changelog and the corresponding version in the extension's config/extension.toml file
• I have added my name to the CONTRIBUTORS.md or my name already exists there