[feat i2g]add feature flag for ingress plan annotation

[shuqz]

Description

• Adds the IngressPlanAnnotation feature gate, which writes the controller's serialized model stack JSON to the alb.ingress.kubernetes.io/dry-run-plan annotation on ingress resources after each reconcile. for group ingresses, it will only be added to member[0] with lowest group order (instead of writing same model to all member ingress)
• in migration tool, for gateway generated from group ingress, add a new annotation to it gateway.k8s.aws/ingress-plan-holder: member[0]'s namespaced name, this will be used later in in-cluster console for model comparison. with this, console can use kubectl to quickly looks up specific ingress and its ingress dry-run-plan annotation

Checklist

• Added tests that cover your change (if possible)
• Added/modified documentation as required (such as the README.md, or the docs directory)
• Manually tested
  example generate gateway from group ingress:

apiVersion: gateway.networking.k8s.io/v1
kind: GatewayClass
metadata:
  name: aws-alb
spec:
  controllerName: gateway.k8s.aws/alb
---
apiVersion: gateway.k8s.aws/v1beta1
kind: LoadBalancerConfiguration
metadata:
  name: my-app-grp-lb-1a6182c3bf
  namespace: plan-test
spec:
  scheme: internet-facing
  tags:
    gateway.k8s.aws/migrated-from: ingress-group/my-app
---
apiVersion: gateway.networking.k8s.io/v1
kind: Gateway
metadata:
  annotations:
    gateway.k8s.aws/ingress-plan-holder: plan-test/api-ingress
  name: my-app-grp-gw-9da8858351
  namespace: plan-test
spec:
  gatewayClassName: aws-alb
  infrastructure:
    parametersRef:
      group: gateway.k8s.aws
      kind: LoadBalancerConfiguration
      name: my-app-grp-lb-1a6182c3bf
  listeners:
  - name: http-80
    port: 80
    protocol: HTTP
---
apiVersion: gateway.networking.k8s.io/v1
kind: HTTPRoute
metadata:
  name: api-ingr-route-bd3a879b19
  namespace: plan-test
spec:
  hostnames:
  - api.example.com
  parentRefs:
  - name: my-app-grp-gw-9da8858351
  rules:
  - backendRefs:
    - name: api-server
      port: 8080
    matches:
    - path:
        type: PathPrefix
        value: /api
---
apiVersion: gateway.networking.k8s.io/v1
kind: HTTPRoute
metadata:
  name: web-ingr-route-02dc49184b
  namespace: plan-test
spec:
  hostnames:
  - www.example.com
  parentRefs:
  - name: my-app-grp-gw-9da8858351
  rules:
  - backendRefs:
    - name: web-server
      port: 80
    matches:
    - path:
        type: PathPrefix
        value: /
---
apiVersion: gateway.networking.k8s.io/v1
kind: HTTPRoute
metadata:
  name: default-route-3f8e26c68d
  namespace: plan-test
spec:
  parentRefs:
  - name: my-app-grp-gw-9da8858351
  rules:
  - backendRefs:
    - name: web-server
      port: 80
    matches:
    - path:
        type: PathPrefix
        value: /
---
apiVersion: gateway.k8s.aws/v1beta1
kind: TargetGroupConfiguration
metadata:
  name: api-serv-tg-confi-e0b76e6463
  namespace: plan-test
spec:
  defaultConfiguration:
    tags:
      gateway.k8s.aws/migrated-from: ingress/plan-test/api-ingress
    targetType: ip
  targetReference:
    name: api-server
---
apiVersion: gateway.k8s.aws/v1beta1
kind: TargetGroupConfiguration
metadata:
  name: web-serv-tg-confi-b70f37291f
  namespace: plan-test
spec:
  defaultConfiguration:
    tags:
      gateway.k8s.aws/migrated-from: ingress/plan-test/web-ingress
    targetType: ip
  targetReference:
    name: web-server

example generated gateway from single ingress

apiVersion: gateway.networking.k8s.io/v1
kind: GatewayClass
metadata:
  name: aws-alb
spec:
  controllerName: gateway.k8s.aws/alb
---
apiVersion: gateway.k8s.aws/v1beta1
kind: LoadBalancerConfiguration
metadata:
  name: standalo-lb-confi-440712d9a1
  namespace: plan-test
spec:
  scheme: internet-facing
  tags:
    gateway.k8s.aws/migrated-from: ingress/plan-test/standalone-ingress
---
apiVersion: gateway.networking.k8s.io/v1
kind: Gateway
metadata:
  name: standalo-gateway-d1df646478
  namespace: plan-test
spec:
  gatewayClassName: aws-alb
  infrastructure:
    parametersRef:
      group: gateway.k8s.aws
      kind: LoadBalancerConfiguration
      name: standalo-lb-confi-440712d9a1
  listeners:
  - name: http-80
    port: 80
    protocol: HTTP
---
apiVersion: gateway.networking.k8s.io/v1
kind: HTTPRoute
metadata:
  name: standalo-route-6a7e65150d
  namespace: plan-test
spec:
  hostnames:
  - standalone.example.com
  parentRefs:
  - name: standalo-gateway-d1df646478
  rules:
  - backendRefs:
    - name: web-server
      port: 80
    matches:
    - path:
        type: PathPrefix
        value: /
---
apiVersion: gateway.k8s.aws/v1beta1
kind: TargetGroupConfiguration
metadata:
  name: web-serv-tg-confi-b70f37291f
  namespace: plan-test
spec:
  defaultConfiguration:
    tags:
      gateway.k8s.aws/migrated-from: ingress/plan-test/standalone-ingress
    targetType: ip
  targetReference:
    name: web-server

• Made sure the title of the PR is a good description that can go into the release notes

BONUS POINTS checklist: complete for good vibes and maybe prizes?! 🤯

• Backfilled missing tests for code in same general area 🎉
• Refactored something and made the world a better place 🌟

[k8s-ci-robot]

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[codecov-commenter]

Codecov Report

❌ Patch coverage is 67.50000% with 13 lines in your changes missing coverage. Please review.
✅ Project coverage is 56.13%. Comparing base (22cdb42) to head (8befc33).
⚠️ Report is 8 commits behind head on main.

Files with missing lines	Patch %	Lines
pkg/ingress2gateway/translate/translate.go	76.00%	5 Missing and 1 partial ⚠️
controllers/ingress/group_controller.go	0.00%	4 Missing ⚠️
controllers/ingress/dryrun.go	80.00%	1 Missing and 1 partial ⚠️
pkg/config/feature_gates.go	0.00%	1 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #4722      +/-   ##
==========================================
+ Coverage   56.09%   56.13%   +0.03%     
==========================================
  Files         388      389       +1     
  Lines       30932    30987      +55     
==========================================
+ Hits        17352    17395      +43     
- Misses      12566    12578      +12     
  Partials     1014     1014              

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[shraddhabang]

Can you write unit tests for this?

[shuqz]

closed in favor of #4728