ConfigProviders abstract over path construction

Fixes issue where certs can't be uploaded in UI in k8s

util/config/provider/baseprovider.py

@@ -109,6 +109,11 @@ class BaseProvider(object):
         indicating that this container requires a restart.
     """
     raise NotImplementedError
+  
+  def get_volume_path(self, directory, file):
+    """ Helper for constructing file paths, which may differ between providers. For example,
+    kubernetes can't have subfolders in configmaps """
+    raise NotImplementedError
 
   def _get_license_file(self):
     """ Returns the contents of the license file. """