Reorganize kubernetes package

[pehala]

• Move Route to kubernetes/openshift
• Remove kubernetes/metrics
  • ServiceMonitor is now at kubernetes
  • Prometheus Client moved to root, as it is not connected to Kubernetes at all
• Create kuadrant package
  • Contains all of the objects/CRs that Kuadrant directly provides
  • Move policy to kuadrant/policy
    • Better reflects the strcture
  • Remove policy suffix from module inside kuadrant/policy
    • from testsuite.kuadrant.policy.rate_limit_policy import RateLimitPolicy -> from testsuite.kuadrant.policy.rate_limit import RateLimitPolicy

Sidenote: Dont worry, this is last PR that significantly moves things around :D