Make renku components and charts work with a forward proxy

[olevski]

When someone is running behind a proxy then they need to inject environment variables in many Renku components and services to make things work.

There should be an option to make this work directly from the helm chart.

The proxy config will have to be also injected in the sessions as well - not just regular renku services.

[Panaetius]

Check with YAT if they will do this, maybe coach