Reevaluate feature parity for Tech Preview of Gateway API

This is a followup to NE-957 in support of NE-1160 and beyond using feature parity with Route API as a basis. Implementation for Tech Preview should be captured in NE-1160 and beyond tech-preview tasking should captured in an appropriate epic.

• Istio's implementation of Gateway API is the focus
• Prioritize Gateway API feature parity with OpenShift Route API

• * Determine Istio Gateway API feature parity with OpenShift Route API
• * Initial performance metrics for Istio Gateway

• Enumerate minimum viable features required for Dev Preview, Tech Preview, GA, etc

Why is this important?

• We need to understand features of Gateway API and Istio Gateway to help us understand what we are delivering in Tech Preview

Acceptance Criteria

• Istio Gateway API can run in tandem with the Route API on OpenShift
• Continue evaluating priorities for upstream and local work using the spreadsheet in
  • https://docs.google.com/spreadsheets/d/1ZlIOQmctIgM1cPniy6h9EkeuQT-XT7-3GShu-DX8cXc/edit#gid=0 
• Documented and prioritized selection of OpenShift Route API features to align with 

Previous Work (Optional):

https://docs.google.com/spreadsheets/d/1ZlIOQmctIgM1cPniy6h9EkeuQT-XT7-3GShu-DX8cXc/edit#gid=0