fix(*) allow verbose log levels

[jpeach]

Summary

When we are in debug logging mode, update the underlying zap log level
so that verbose logs up to level 10 will be emitted.

This fixes #2350

Full changelog

N/A

Issues resolved

N/A

Documentation

N/A

Testing

2021-07-12T15:53:53.666+1000	LEVEL(-2)	proxy-template-resolver	falling back to the default ProxyTemplate since there is no best match	{"dataplane": {"Mesh":"default","Name":"greenling"}, "templates": null}

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

Backwards compatibility

• Add backport-to-stable label if the code is backwards compatible. Otherwise, list breaking changes.

[codecov-commenter]

Codecov Report

Merging #2351 (fd58d5e) into master (82c6818) will increase coverage by 0.38%.
The diff coverage is 0.00%.

@@            Coverage Diff             @@
##           master    #2351      +/-   ##
==========================================
+ Coverage   52.14%   52.52%   +0.38%     
==========================================
  Files         875      879       +4     
  Lines       47801    47842      +41     
==========================================
+ Hits        24925    25129     +204     
+ Misses      20855    20667     -188     
- Partials     2021     2046      +25     

Impacted Files	Coverage Δ
pkg/log/logger.go	67.39% <0.00%> (ø)
pkg/insights/components.go	70.00% <0.00%> (-30.00%)	⬇️
pkg/insights/resyncer.go	64.70% <0.00%> (-0.85%)	⬇️
...kg/plugins/resources/k8s/native/pkg/test/within.go	100.00% <0.00%> (ø)
api/internal/util/proto/proto.go	70.00% <0.00%> (ø)
...k8s/native/controllers/proxytemplate_controller.go	0.00% <0.00%> (ø)
api/internal/util/proto/types.go	100.00% <0.00%> (ø)
pkg/xds/generator/direct_access_proxy_generator.go	83.90% <0.00%> (+1.14%)	⬆️
api/mesh/v1alpha1/dataplane_helpers.go	80.16% <0.00%> (+1.68%)	⬆️
pkg/core/resources/manager/cache.go	84.41% <0.00%> (+5.19%)	⬆️
... and 7 more

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