Create "User guide - Tuto / How to"

Create a gitpage to help using matrix app.

• create giltab-ci gitpage
• Tuto-how to
  • who
  • where
  • Main analysis workflow
  • how-to
    • load data
    • explore datas
      • tables
      • volcano
      • stripcharts
    • PCA
    • venn
    • heatmap
    • enrichr
  • FAQ
    • how does it works? usage cost?
    • [ ]
    • what does it [not] do?
    • input tables format
    • export images and tables?
    • [ ]