As a cluster-administrator, I want to know what add-on component configurations are supported in the ServiceMeshControlPlane, so that I can configure the SMCP for my mesh.

Create a module to document the configuration settings in under `spec.addons` in the SMCP and add it to the ossm-reference-smcp.adoc assembly file.

This section covers:

• 3scale  (Check to see if this is already covered in the 3scale docs?)
• grafana
• jaeger (already documented in ossm-reference-jaeger.adoc assembly)
• kiali (will be documented in ossm-reference-kiali.adoc assembly once OSSMDOC-168 is complete)
• prometheus
• NOTE: stackdriver is not supported in the product, do not include this section

GitHub reference documentation - https://github.com/maistra/api/blob/maistra-2.1/docs/crd/maistra.io_ServiceMeshControlPlane_AddonsConfig_v2.adoc