ADD strict network policies to all core Anubis services

There are some network policies that are defined in [network-policy.yml](https://github.com/GusSand/Anubis/blob/master/k8s/chart/templates/network-policy.yml). These policies are only on the places where users have some level of execution on the Anubis cluster (like the theia pods and autograde pipelines).

We need to add policies to govern other places like the web and api deployments.

Use this tool for visualizing and editing network policies https://editor.cilium.io/

- [ ] write network policies
- [ ] API
- [ ] WEB
- [ ] RPC-default
- [ ] RPC-theia
- [ ] RPC-regrade