Enhance Knative integration

[leochr]

Knative project has evolved since the last time the support for it in Liberty Operator was enhanced. Reevaluate the integration and make necessary improvements.

Also, consider supporting Knative with newly added capabilities (if possible): manage TLS (relevant Knative doc), semeru cloud compiler, autoscaling (with KPA), security context, etc

Also check if these limitations still apply:

• "Startup probe is not fully supported by Knative, thus .spec.probes.startup does not apply when Knative service is enabled." (from doc)
• OpenShift Serverless (Knative) does not support HTTPS on a pod level

[halim-lee]

Startup probe is still not supported by Knative. Someone tried adding support for startupProbe and the PR got closed: https://github.com/knative/serving/pull/13700

• https://github.com/knative/serving/issues/10037
• https://github.com/knative/serving/pull/12565