[web] Add more context to the ProjectsList empty screen

[jmaupetit]

Purpose

If a new user login to crick without prior knowledge of the Watson project, he may need more context about the software architecture, and a step-by-step guide on how to make it work from scratch.

Proposal

The ProjectsList empty screen (web/src/ProjectsList/Empty.js) should contain the following documentation:

• [ ] Watson (client) & Crick (API server) architecture
• [ ] Watson quick start guide (installation & first frame creation)
• [x] Watson configuration
• [x] Watson sync