docs(init): create documentation website using vitepress

- 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

.devcontainer/docker-compose.yml

@@ -4,7 +4,7 @@ services:
     volumes:
       # Mounts the project folder to '/workspace'. While this file is in .devcontainer,
       # mounts are relative to the first file in the list, which is a level up.
-      - .:/castopod-host:cached
+      - .:/castopod:cached
 
     # Overrides default command so things don't shut down after the process ends.
     command: /bin/sh -c "while sleep 1000; do :; done"