Be explicit about which generation we're working with in the code

[vtnate]

Expected Behavior

We now have models that will only work with a given generation of district system. We should arrange the file structure to make it clear which are shared and which belong to a specific district system.

Be explicit about which generation we're working with here. Should be explicit if statements, or if/when we use minimum python 3.10 we could use a case statement.

We should also improve the folder structure where models that only apply to a give generation of district are clearly separated out.

Actual Behavior

4G is assumed, not explicitly stated, in the else statement

Steps to Reproduce

Version Information