Documentation

What is this branch about

• Documentation of PELICAN and PPE

What did I do

• Shortend namespace names:
  • Renamed namespace PropagationParameterEngine to PPE
  • Renamed namespace PropagationModules to PropModules
  • Renamed namespace PropagationParameters to PropParams
• Added using typedefs to reduce clutter and improve doxygen readability
• Added PropModules readme. How to create and use a module. How does factory work
• Added Factory readme.
• Added Functionality readme. Dont know about the name but it tries to explain the components of PELICAN and what they do.

Missing

• The webidl.md is TODO. There should be some readme explaining how the config files works and how to add new module configs to the webidl. However, this depends on the final polyscribe function. I also currently don't know how some types like strings work in the webidl. Add (at least a rough) docu later once polyscribe works. Maybe also link from the PropModules readme as one has to create a new module config in the webidl.