Add get auto image-policy and refactor

This factors the get command implementation so that the control flow
is generic and relies on a handful of methods, then uses that to add
`get auto image-policy` and to rewrite `get auto image-repository`.

Signed-off-by: Michael Bridgen <michael@weave.works>

docs/cmd/flux_get_auto.md

@@ -26,5 +26,6 @@ The get auto sub-commands print the statuses of the automation objects.
 ### SEE ALSO
 
 * [flux get](flux_get.md)	 - Get sources and resources
+* [flux get auto image-policy](flux_get_auto_image-policy.md)	 - Get ImagePolicy statuses
 * [flux get auto image-repository](flux_get_auto_image-repository.md)	 - Get ImageRepository statuses
 

docs/cmd/flux_get_auto_image-policy.md

@@ -0,0 +1,44 @@
+## flux get auto image-policy
+
+Get ImagePolicy statuses
+
+### Synopsis
+
+The get auto image-policy command prints the status of ImagePolicy objects.
+
+```
+flux get auto image-policy [flags]
+```
+
+### Examples
+
+```
+  # List all image policies and their status
+  flux get auto image-policy
+
+ # List image policies from all namespaces
+  flux get auto image-policy --all-namespaces
+
+```
+
+### Options
+
+```
+  -h, --help   help for image-policy
+```
+
+### Options inherited from parent commands
+
+```
+  -A, --all-namespaces      list the requested object(s) across all namespaces
+      --context string      kubernetes context to use
+      --kubeconfig string   path to the kubeconfig file (default "~/.kube/config")
+  -n, --namespace string    the namespace scope for this operation (default "flux-system")
+      --timeout duration    timeout for this operation (default 5m0s)
+      --verbose             print generated objects
+```
+
+### SEE ALSO
+
+* [flux get auto](flux_get_auto.md)	 - Get automation statuses
+