feat(config): make all all-in-one dbless manifests use multi-gw

[czeslavo]

What this PR does / why we need it:

• Makes all all-in-one DB-less manifests use multi-gw config.
• Renames old single-Deployment all-in-one-dbless.yaml to all-in-one-dbless-legacy.yaml.
• Uses a projected volume instead of a static SA secret in the multi-gw proxy deployment.
• Aligns all the affected E2E tests to work with multi-gw config as expected.

E2E tests run: https://github.com/Kong/kubernetes-ingress-controller/actions/runs/4308118461

Which issue this PR fixes:

Closes #3423.

PR Readiness Checklist:

Complete these before marking the PR as ready to review:

• the CHANGELOG.md release notes have been updated to reflect any significant (and particularly user-facing) changes introduced by this PR

[codecov]

Codecov Report

Patch coverage has no change and project coverage change: +0.3 🎉

Comparison is base (bc86d7b) 72.6% compared to head (37104a4) 72.9%.

Additional details and impacted files

@@           Coverage Diff           @@
##            main   #3629     +/-   ##
=======================================
+ Coverage   72.6%   72.9%   +0.3%     
=======================================
  Files        131     131             
  Lines      15723   15723             
=======================================
+ Hits       11423   11474     +51     
+ Misses      3546    3489     -57     
- Partials     754     760      +6     

Impacted Files	Coverage Δ
...nternal/controllers/gateway/tlsroute_controller.go	71.4% <0.0%> (-2.1%)	⬇️
internal/konnect/client.go	42.1% <0.0%> (ø)
...nternal/controllers/gateway/udproute_controller.go	73.7% <0.0%> (+2.1%)	⬆️
...ntrollers/configuration/kongadminapi_controller.go	62.9% <0.0%> (+62.9%)	⬆️

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