Improve Jaeger tracing documentation

[W3D3]

The docs in docs/TRACING.md refer to hardcoded versions of the jaeger-operator helm chart that is incompatible with more recent K8s versions.

We should cut everything from that documentation page that is not Unguard related (like the name of the jaeger-agent that has to match) and simply link to an up-to-date documentation page that explains how to install Jaeger on K8s like https://www.jaegertracing.io/docs/1.49/operator/ or similar.

We could also recommend not to use the operator, as it requires cert-manager in recent versions (which makes it more work to setup for something that will be used for local dev only anways) and just install the Jaeger helm chart using:

helm install jaeger jaegertracing/jaeger

I would also suggest getting rid of /k8s-templates/jaeger in the process.