Remove docs references to Knative

[Ben Taussig]

Version

main (1.16.x beta)

Describe the requested changes

• Knative has been deprecated for some time
  • See #5707 , which was closed in December 2021
• As seen in some recent PRs, we still include Knative in our helm values.go and associated generated documentation

  gloo/docs/content/reference/values.txt

  Lines 7 to 17 in 6bccd5d

   |settings.integrations.knative.enabled|bool|false|enabled knative components| 
   |settings.integrations.knative.version|string|0.10.0|the version of knative installed to the cluster. if using version < 0.8.0, Gloo Edge will use Knative's ClusterIngress API for configuration rather than the namespace-scoped Ingress| 
   |settings.integrations.knative.proxy.image.tag|string|<release_version, ex: 1.2.3>|The image tag for the container.| 
   |settings.integrations.knative.proxy.image.repository|string|gloo-envoy-wrapper|The image repository (name) for the container.| 
   |settings.integrations.knative.proxy.image.digest|string||The hash digest of the container's image, ie. sha256:12345....| 
   |settings.integrations.knative.proxy.image.registry|string||The image hostname prefix and registry, such as quay.io/solo-io.| 
   |settings.integrations.knative.proxy.image.pullPolicy|string||The image pull policy for the container. For default values, see the Kubernetes docs: https://kubernetes.io/docs/concepts/containers/images/#imagepullpolicy-defaulting| 
   |settings.integrations.knative.proxy.image.pullSecret|string||The image pull secret to use for the container, in the same namespace as the container pod.| 
   |settings.integrations.knative.proxy.image.variant|string||Specifies the version of the data-plane containers to deploy. Can take the values 'standard', 'fips', 'distroless', 'fips-distroless'. Defaults to standard. (Enterprise-only feature.)| 
   |settings.integrations.knative.proxy.image.fipsDigest|string||[Deprecated] Use 'variant=fips' and 'digest=...' instead. The hash digest of the container's fips image, ie. sha256:12345....  Only consumed if fips=true| 
   |settings.integrations.knative.proxy.image.fips|bool||[Deprecated] Use 'variant=fips' instead. If true, deploys a version of the data-plane containers that is built with FIPS-compliant crypto libraries. (Enterprise-only feature)| 

• Due to the way we generate documentation for the images used by Gloo Edge, it appears that we continue to support Knative like we do our other images

Link to any relevant existing docs

https://docs.solo.io/gloo-edge/latest/reference/helm_chart_values/enterprise_helm_chart_values/

Browser Information

No response

Additional Context

No response

[Jenny Shu]

also see similar issue #5708

i'm not sure we should delete it yet - should check on status of #6737