Added ID to reason template 2.16.840.1.113883.10.20.24.3.88

Added an ID, using the new `identifier_for` method, to the reason template, `2.16.840.1.113883.10.20.24.3.88`. 

Also refactored `_2.16.840.1.113883.10.20.24.3.23.cat1.erb` to use the reason template, to reduce code duplication.