feat: add /status/ready function

[tao12345666333]

ref: https://github.com/Kong/kubernetes-ingress-controller/issues/5068

This endpoint should be used to health-check Kong nodes. This can be health checks from orchestration frameworks like k8s or by load-balancers fronting Kong nodes that proxy traffic. This endpoint returns 200 only after the Kong node has configured itself and is ready to start proxying traffic.

https://docs.konghq.com/gateway/api/status/latest/#/default/get_status_ready

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Codecov Report

Attention: Patch coverage is 60.86957% with 18 lines in your changes missing coverage. Please review.

Project coverage is 59.58%. Comparing base (afe0c7b) to head (a2bc45b).

Files	Patch %	Lines
kong/client.go	52.63%	14 Missing and 4 partials :warning:

Additional details and impacted files

@@            Coverage Diff             @@
##             main     #454      +/-   ##
==========================================
- Coverage   59.61%   59.58%   -0.04%     
==========================================
  Files          71       71              
  Lines        4408     4449      +41     
==========================================
+ Hits         2628     2651      +23     
- Misses       1166     1180      +14     
- Partials      614      618       +4     

Flag	Coverage Δ
2.1	35.62% <23.91%> (-0.20%)	:arrow_down:
2.2	48.03% <23.91%> (-0.32%)	:arrow_down:
2.3	48.66% <23.91%> (-0.32%)	:arrow_down:
2.4	48.70% <23.91%> (-0.32%)	:arrow_down:
2.5	48.70% <23.91%> (-0.32%)	:arrow_down:
2.6	48.70% <23.91%> (-0.32%)	:arrow_down:
2.7	50.39% <23.91%> (-0.34%)	:arrow_down:
2.8	50.39% <23.91%> (-0.34%)	:arrow_down:
3.0	54.52% <23.91%> (-0.38%)	:arrow_down:
3.1	56.14% <23.91%> (-0.39%)	:arrow_down:
3.2	56.14% <23.91%> (-0.39%)	:arrow_down:
3.3	56.52% <60.86%> (-0.01%)	:arrow_down:
3.4	58.88% <60.86%> (-0.03%)	:arrow_down:
3.5	56.70% <60.86%> (-0.01%)	:arrow_down:
3.6	56.70% <60.86%> (-0.01%)	:arrow_down:
community	43.78% <60.86%> (+0.11%)	:arrow_up:
enterprise	57.96% <56.52%> (-0.07%)	:arrow_down:
integration	59.58% <60.86%> (-0.04%)	:arrow_down:

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[sandromodarelli]

closing as https://github.com/Kong/kubernetes-ingress-controller/issues/5068 has been closed as stale