chore: clean up coverage

[shaneutt]

What this PR does / why we need it:

This patch reduces the packages we want coverage
for to pkg/ and internal/ (where all our code lives
now minus scripts and some build tools) and turns
on unit tests during the integration test runs to
capture more coverage data.

[codecov]

Codecov Report

Merging #1611 (e8b7247) into next (0a503e5) will increase coverage by 16.49%.
The diff coverage is n/a.

@@             Coverage Diff             @@
##             next    #1611       +/-   ##
===========================================
+ Coverage   46.13%   62.63%   +16.49%     
===========================================
  Files          71       82       +11     
  Lines        6745     7180      +435     
===========================================
+ Hits         3112     4497     +1385     
+ Misses       3262     2358      -904     
+ Partials      371      325       -46     

Flag	Coverage Δ
integration-test	62.63% <ø> (+16.49%)	⬆️

Flags with carried forward coverage won't be shown. Click here to find out more.

Impacted Files	Coverage Δ
internal/ctrlutils/utils.go	93.75% <0.00%> (-2.09%)	⬇️
...et/typed/configuration/v1/fake/fake_kongingress.go	0.00% <0.00%> (ø)
...t/typed/configuration/v1/fake/fake_kongconsumer.go	0.00% <0.00%> (ø)
internal/cmd/main.go	0.00% <0.00%> (ø)
...configuration/v1/fake/fake_configuration_client.go	0.00% <0.00%> (ø)
...set/typed/configuration/v1/fake/fake_kongplugin.go	0.00% <0.00%> (ø)
...guration/v1beta1/fake/fake_configuration_client.go	0.00% <0.00%> (ø)
pkg/clientset/fake/clientset_generated.go	0.00% <0.00%> (ø)
...yped/configuration/v1beta1/fake/fake_tcpingress.go	0.00% <0.00%> (ø)
pkg/clientset/fake/register.go	100.00% <0.00%> (ø)
... and 32 more

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[mflendrich]

I personally don't like the idea of running unit tests under the "integration tests" target, but I won't block this change if this helps with more accurate codecov 👍