generate structured helm values reference docs rather than table-style

[ilackarms]

we currently generate reference docs for our helm values apis (eg in gloo-mesh charts) in table format. this can quickly get become unreadable as the values schema represents a type schema which can have many layers of nesting as well as repetition of types.

for readability purposes, we should be generating the same kind of api reference for our helm values the same way we generate for our CRDs - structured object documentation like we do for our CRD apis