Transition of documentation to gitbook

Discuss and consider using gitbook to document VOLTHA.

Issues to discuss:

• Where will documentation be located?
  • Aggregation of documents in multiple repos into a single site
• Documentation workflow
  • Generation of images/diagrams
  • How to update documentation on released versions/branches
• Is there existing documentation in the wiki that should be converted?
• Publishing and QA pipeline for docs
  • Verification of docs: markdown lint (ruby) and linkchecker (python)
  • Building with gitbook (npm)
  • Publishing on a website (need to create this, like guide.opencord.org - maybe voltha.opencord.org ?)