Add high level conceptual diagram(s) of GlooMesh + Modules

[Boes-man]

Describe the requested changes Add high level conceptual diagram of GME + the modules, specifically GMG initially. Have a diagram at each mudules oerview page? Ideally it should be based of the upstream Istio Architecture diagram, showing the control plane and data plane. GMG should be at the ingress edge of the mesh in the data plane.

Link to any relevant existing docs https://istio.io/latest/docs/ops/deployment/architecture/ Put the diagram here for GMG?: https://docs.solo.io/gloo-mesh-enterprise/latest/concepts/modules/gateway_module/ Have attached a draft, starter for GMG

[artberger]

Related request from Steve for a whole-picture architecture diagram:

• Slack thread
• My notes