added option to use the lost-test image

[JonasGoebel]

Added option to use the lost-test docker image

Description

When using quick_setup.py the lost-test image can be used (instead of lost) for accessing images from testing stage.
Use the --testing True argument to create the LOST environment with the lost-test-image.

Types of changes

• [ ] Bug fix (non-breaking change which fixes an issue)
• [ x] New feature (non-breaking change which adds functionality)
• [ ] Breaking change (fix or feature that would cause existing functionality to change)
• [ x] I have read the CONTRIBUTING document.
• [ x] My code follows the code style of this project.
• [ ] My change requires a change to the documentation.
• [ ] I have updated the documentation accordingly.
• [ ] I have added tests to cover my changes.
• [ ] All new and existing tests passed.