Service Shutdown and Cleanup Enhancements

This release addresses issues with the service container shutdown process and container cleanup processes.

Core Changes:

• Changes service shutdown process from "detached" fork to spawned, parallel processes which occur before parent process exits
• Improves output for failed shutdowns so user is immediately aware
• Improves --cleanup and --cleanup-all to output more verbose information about process

Additional Changes

• Added output for invalid devlab.yml config to better explain config load failures.