Clean Up Local and Flexible Descriptor Value Sets

Clean up descriptor value sets to make them semantically more sensible and remove outliers. Use deprecation initially to keep the changes as non-breaking.

Focus on sets classified as local or flexible in the UDM documentation.

To "remove" a value from a descriptor, we don't actually delete the values as that could break an implementation that is using these values. Instead, we deprecate those values.

For descriptors, deprecation is pretty straightforward. Within the XML file for that descriptor, add "DEPRECATED: " before the ShortDescription and Description values. As an example, look at the Emergency value here: https://github.com/Ed-Fi-Alliance-OSS/Ed-Fi-Standard/blob/main/Descriptors/RelationDescriptor.xml.

And move deprecated items to the end of the file.