Preflight

[marccampbell]

This adds initial support for running e2e preflights. I've refactored them to not be dependent on the collector/CRD running. This allows the CLI to execute them and manage the collection and analysis phases independent of the CRD. But the CRD continues to share the same codepath.

A single analyzer is implemented:

apiVersion: troubleshoot.replicated.com/v1beta1
kind: Preflight
metadata:
  name: preflight-sample
spec:
  analyzers:
    - clusterVersion:
        outcomes:
          - fail:
              when: "< 1.14.0"
              message: You need more kubernetes
          - warn:
              when: "< 1.15.0"
              message: You have barely enough kubernetes
          - pass:
              message: Good job keeping k8s current