Switch logging library from logrus to klog.

[andriyDev]

fixes #35.

Previously, the primary logging library was logrus. However, triage-party (one of our dependencies) used klog. Since this is more standard for kubernetes, this switches us to klog. Some minor behavior has changed, for example the few lines using logrus.Debugf have been replaced with klog.Infof.

Note: We still implicitly depend on logrus through github.com/spf13/viper. In my use case, no log messages were produced by logrus though. We likely could remove viper since its only purpose is allowing variables to be defaulted to environment variables (which is a very limited usage).

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[googlebot]

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[medyagh]

lgtm wdyt ? @tstromberg

[medyagh]

@andriyDev lint is failing

[andriyDev]

@medyagh Fixed!

[tstromberg]

LGTM