this fixes the adblocker loading viewer error

- rename castopod icons and logos
- fix nlnet logo link
- add castopod icon as logo
- set twitter
card to summary_large_image
- update README.md

- 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