Standardize usage of XSD integer datatypes

In the 2.0 XSD there are three different usages of built-in integer datatypes
xs:integer, xs:int, and xs:positiveInteger. Both xs:int and xs:positiveInteger are restrictions of xs:integer to limit the valid range.

There are two usages of xs:integer and one usage of xs:positiveInteger. We suggest converting everything to xs:int, where the xs:positiveInteger would be an xs:int with a min value of 1.

xs:positiveInteger - is used to indicate the priority order of telephone numbers
xs:Integer - is used on number of school days under discipline action

See https://www.w3.org/TR/xmlschema-2/#built-in-datatypes for more detail on the relationship between the three built-in types.

While this is a data type change there is no practical data impact