Ubuntu 20.04 Integration Tests Updated with Docker-Compose 1.28.2 and Parallel Execution_FEATURE

Ubuntu 20.04 is now used to run integration tests, docker-compose version used to run integration tests is updated to 1.28.2. Environment variables now take effect on docker-compose. Rework test_dictionaries_all_layouts_separate_sources to allow parallel run. #20393 (Ilya Yatsishin).