Refactoring to be the main backend

[rngadam]

preparing to integrate functionality from louis-backend (will remove louis-backend and rename louis-crawler to louis-backend)

Refactoring:

• moving source files to be into their own subdirectories
  • louis.crawler
  • louis.db
  • louis.models
  • add agent and its api
  • move code from louis-backend to louis-crawler