Functional Tests for Split Data and Control Plane Architecture

[mpstefan]

As a maintainer of NGF
I want to create new functional tests to cover the functionality of the split data and control plane architecture
So that I ensure that the architecture is working as intended.

Acceptance

• Validate that the NGINX Proxy properly attaches to the Gateway object
• Validate that multiple Gateways work as intended

[mpstefan]

This should be covered by existing conformance tests for the Gateway API