Mutagen (Mac) support and stability improvements

What is inside?

• Mutagen support, allows to improve Mac performance
• You can run frontend container on the first install - the popular issue is now eliminated
• No more code duplications. One start script for most cases. Accepts options.
• Theme is no longer build in the app container if frontend container is in the stack
• Proper sequences in docker-compose files: depends_on and wait-for-it
• Bump of docker-compose version to 3.6