feat(gateway): add listener connection limits

[michaelbeaumont]

Checklist prior to review

The big line change is due to golden files updates

Adds

listeners:
  - ...
    resources:
      connectionLimit: 10000

to MeshGateway via Runtime Discovery Service (RTDS).

• validation: blocked on feat(gateway): validate listeners for collapsibility #4765

• Link to docs PR or issue -- Document production usage of MeshGateway kuma-website#931
• Link to UI issue or PR -- none
• Is the issue worked on linked? -- Closes Gateway listener connection limit support #3303, closes xDS layered runtime support #3302
• Unit Tests --
• E2E Tests --
• Manual Universal Tests --
• Manual Kubernetes Tests --
• Do you need to update UPGRADE.md? --
• Does it need to be backported according to the backporting policy? --

[codecov-commenter]

Codecov Report

Merging #4755 (11389f9) into master (ecdf217) will increase coverage by 0.02%.
The diff coverage is 66.94%.

@@            Coverage Diff             @@
##           master    #4755      +/-   ##
==========================================
+ Coverage   46.42%   46.44%   +0.02%     
==========================================
  Files         690      690              
  Lines       46998    47086      +88     
==========================================
+ Hits        21817    21871      +54     
- Misses      23256    23290      +34     
  Partials     1925     1925              

Impacted Files	Coverage Δ
api/mesh/v1alpha1/gateway.pb.go	6.85% <2.63%> (-0.90%)	⬇️
pkg/plugins/runtime/gateway/generator.go	84.16% <91.30%> (+1.31%)	⬆️
pkg/core/resources/apis/mesh/gateway_validator.go	88.19% <100.00%> (+1.27%)	⬆️
pkg/plugins/runtime/gateway/listener_generator.go	93.54% <100.00%> (+1.88%)	⬆️
pkg/xds/bootstrap/template_v3.go	96.17% <100.00%> (+0.14%)	⬆️
pkg/xds/generator/direct_access_proxy_generator.go	90.90% <0.00%> (+1.13%)	⬆️
pkg/core/resources/manager/cache.go	88.31% <0.00%> (+2.59%)	⬆️

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