- add contributors list to readme and docs' index page
- add CONTRIBUTING.md file redirecting to docs website
- add "translate castopod" section to guidelines

this fixes the adblocker loading viewer error

- rename podlibre to adaures
- rename castopod-host to castopod
- simplify README and redirect to docs site
- move INSTALL and UPDATE docs
- add new gitlabci pipeline to deploy docs
- upgrade node to v16 in Dockerfile