Adds final challenge README
First draft of the final challenge
Adds first description of services
Adds authentication flow diagram
Adds authentication flow diagram
Adds info about more systems
Fixes final challenge description
Adds item tracking system description
Adds report system description
Fixes JSON syntax
Adds all remaining info
Adds missing links
Adds systems overview
Fixes overview image
Fixes the markdown image syntax
Translates remaining text of the overview image
Cache busts the overview image
Merge pull request #2 from walski/final-challenge

Final challenge