Refactor for v2

[slok]

From the changelong:

• Refactor controller package.
• Refactor metrics package.
• Refactor log package.
• Remove operator concept and remove CRD initialization in favor of using only
  controllers and let the CRD initialization outside Kooper (e.g CRD yaml).
• Default resync time to 3 minutes.
• Default workers to 3.
• Disable retry handling on controllers in case of error by default.
• Remove tracing.
• Minimum Go version v1.13 (error wrapping required).
• Refactor Logger with structured logging.
• Add Logrus helper wrapper.
• Refactor to simplify the retrievers.
• Refactor metrics recorder implementation including the prometheus backend.
• Refactor internal controller queue into a decorator implementation approach.
• Remove Delete method from controller.Handler and simplify to only Handle method
• Add DisableResync flag on controller configuration to disable the resync of all resources.