Add handling of repository routing rules

[larhauga]

This pull requests adds support for adding routing rules.

Example configuration:

repository:
  routingRules:
    - name: go-internal
      description: internal golang packages with authentication
      mode: ALLOW
      matchers:
        - ".*/github.com/<private-organization>/.*"
...
    - name: athens
      recipeName: go-proxy
      online: true
      routingRuleName: go-internal
      attributes:
        proxy:
          remoteUrl: http://athens.athens.svc.cluster.local:8080
          contentMaxAge: 10080
          metadataMaxAge: 1440
...