Create a Wiki to better document project

[nhamilakis]

Improve documentation by creating a wiki and adding the following information :

• Home page (use the readme as home page)
• How to install platform & dependencies
• CLI usage & administration
• Quick-start (a how-to guide on setting up challenges & data for the platform)
• Configuration (a guide on what options are configurable)
• A detailed guide on how to set up evaluation pipelines
• A detailed guide for leaderboards
• Technical documentation
  • Databases
  • API
  • Data management