misc things for readme

[meghalithic]

• add provenance of code (both to readme and as headers in code / code in containers)
• specify & point to containers containers (order should follow 1-4 in Intro) under "Workflow components", which will be section 2
  • merge section 5 (Codes and Containers location) here
• remove Stage 2 and Step 5 and put on Morphology Analysis repo
• create new "get started section", which will become section 3
  • subheaders would be "set up requirements", "download models", "usage and test", "quick start with OSC"