Build and publish styleguidist documentation

Create a .gitlab-ci.yml job to:

• listen for changes to react-component projects
• checkout the components from all react-component projects
• parse package.json from all react-component projects and calculate a combined package.json
• build a single page styleguidist document
• publish to github pages *

* on discussion, this seems the best option for this at the moment - however, please review this when refining.