Consider moving where metadata classes are defined
Observatory.py was placed in geomagio/api/ws. I have always wondered about this, and I think we might want to reconsider how/where these metadata classes get defined. At first glance, a natural place would have been under the metadata factory folder, but looking closer, one sees that that factory actually depends on the api (circular dependency?). Maybe Jeremy's/Payton's intent was to isolate the api for eventual removal to a separate project, but I don't remember any discussions about this.