Allow FetchEnvs to pull data from anywhere on a resource

[alewitt2]

The base case im trying to solve with this is to allow a mustache template pull the resorceVersion from a cm/secret's metadata so that we can restart a deployment when it changes.

instead of key which we use to know where in the cm/secret .data section to pull from, if a user specifies path we should know to look outside the data section and pull whatever they tell us to.

Some users might want to grab whole json objects or boolean values. In this case we probably need a way to convert them into a string, so a new string type should be added to do the .toString() to the value if needed.

ex:

env:
  - name: rv # name of the key the fetched data will be assigned to
    valueFrom:
      configMapKeyRef:
        path: metadata.resourceVersion # path to key within configmap
        name: cluster-info # configmap name
        namespace: kube-system # configmap namespace
        type: string # tells fetchEnvs to stringify the fetched key if its not already