ProviderCategory descriptors should be aligned with Ed-Fi standard practice and defined

The current Ed-Fi provider categories are hard to understand and have no definitions. They also use abbreviations, which departs from standard Ed-Fi practice of including full phrases to enhance field usability. These issues need to be addressed.

Original ticket is https://tracker.ed-fi.org/browse/DATASTD-329 Values can be seen here: https://github.com/Ed-Fi-Alliance/Ed-Fi-Standard/blob/master/v3.2/Descriptors/ProviderCategoryDescriptor.xml