Inference Extension: add NGF to Inference docs

[sjberman]

The inference extension docs mention various implementations that support the API. For example, the Getting Started guide. NGF should have a presence there once we release with Inference Extension support.

Any other locations in the docs that mention supported implementations should also be updated.
eg: https://gateway-api-inference-extension.sigs.k8s.io/implementations/gateways/

Acceptance

• once released, NGF should be present in the Gateway API inference extension docs.
• add inference conformance report to their repo

[ciarams87]

Conformance profile report:

apiVersion: gateway.networking.k8s.io/v1
date: "2025-10-28T14:18:58Z"
gatewayAPIChannel: experimental
gatewayAPIVersion: v1.3.0
implementation:
  contact:
  - https://github.com/nginx/nginx-gateway-fabric/discussions/new/choose
  organization: nginx
  project: nginx-gateway-fabric
  url: https://github.com/nginx/nginx-gateway-fabric
  version: 2.2.0
kind: ConformanceReport
mode: default
profiles:
- core:
    result: success
    statistics:
      Failed: 0
      Passed: 9
      Skipped: 0
  name: Gateway
  summary: Core tests succeeded.

This should placed into https://github.com/kubernetes-sigs/gateway-api-inference-extension/tree/main/conformance/reports/v1.0.2/gateway under a new nginx-gateway-fabric folder and requires a corresponding README.md file following the guidelines here