feat(kuma-cp): customize envoy log level

[jakubdyszkiewicz]

Summary

Expose Envoy log level. I did not want to introduce meaningless log levels to kuma-dp itself, so it's a separate flag.
On Kubernetes, you can customize it with annotation kuma.io/envoy-log-level.
If you want to customize it on all envoys, you can either use KUMA_RUNTIME_KUBERNETES_INJECTOR_SIDECAR_CONTAINER_ENV_VARS or ContainerPatch.

Issues resolved

Fix #1820

Documentation

• In progress

Testing

• Unit tests
• E2E tests
• Manual testing on Universal
• Manual testing on Kubernetes

Backwards compatibility

- [ ] Update UPGRADE.md with any steps users will need to take when upgrading.
- [ ] Add backport-to-stable label if the code follows our backporting policy

[codecov-commenter]

Codecov Report

Merging #4438 (c3e98a2) into master (fdb3751) will decrease coverage by 0.02%.
The diff coverage is 100.00%.

@@            Coverage Diff             @@
##           master    #4438      +/-   ##
==========================================
- Coverage   55.51%   55.48%   -0.03%     
==========================================
  Files         941      941              
  Lines       57669    57675       +6     
==========================================
- Hits        32014    32003      -11     
- Misses      23113    23116       +3     
- Partials     2542     2556      +14     

Impacted Files	Coverage Δ
pkg/config/app/kuma-dp/config.go	63.47% <ø> (ø)
pkg/plugins/runtime/k8s/metadata/annotations.go	100.00% <ø> (ø)
app/kuma-dp/cmd/run.go	67.98% <100.00%> (+0.31%)	⬆️
app/kuma-dp/pkg/dataplane/envoy/envoy.go	79.34% <100.00%> (ø)
pkg/plugins/runtime/k8s/containers/factory.go	93.84% <100.00%> (+0.12%)	⬆️
pkg/plugins/common/postgres/connection.go	50.00% <0.00%> (-16.67%)	⬇️
pkg/clusterid/creator.go	73.33% <0.00%> (-13.34%)	⬇️
pkg/metrics/store/counter.go	74.54% <0.00%> (-10.91%)	⬇️
pkg/core/runtime/component/component.go	83.87% <0.00%> (-9.68%)	⬇️
pkg/plugins/resources/postgres/migrate.go	55.55% <0.00%> (-6.35%)	⬇️
... and 10 more

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[parkanzky]

LGTM