Default entity types do not show up on GET /<application> endpoint when there are 0 entities

Default entity types do not show up on GET /<application> endpoint when there are 0 entities of that type (none in the collection)

e.g. users

Due to this the portal may not show the default collections when there are 0 entities in the collection. This is happening now that graph edges are cleaned up properly, but we should discuss showing these since they are default, reserved typed entities in Usergrid.