Support source IP resolving for HTTP traffic in Istio service mesh.
If X-Forwarded-For HTTP request header is present, replace the source address with the left-most address in X-Forwarded-For (earliest in Envoy implementation of this header).
This allows Mizu to resolve source IPs in Istio service meshes, if the use_remote_address option is on. Added instructions on how to turn it on.
- Rename --istio flag to the more general --service-mesh
- Rename internal variables, consts and structures to reflect this conceptual change
- Update the docs accordingly