Python library for consuming OpenStack sevice-types-authority data

The OpenStack Service Types Authority contains information about official
OpenStack services and their historical service-type aliases.

The data is in JSON and the latest data should always be used. This simple
library exists to allow for easy consumption of the data, along with a built-in
version of the data to use in case network access is for some reason not
possible and local caching of the fetched data.