Provide usable end user documentation

This merge request comes with changes that reimplement help.ecobytes.net with

• a new theme https://lab.allmende.io/ecobytes/commons/hugo-theme-ecolearn/merge_requests/3
• a better content structure https://lab.allmende.io/ecobytes/commons/documentation/merge_requests/1
• a simpler deployment integration

that allow to fix #1 (moved).