[WIP] Ma firearm data import

[kevingranade]

Summary

None

Purpose of change

This is a process for importing govt-sourced firearm possession data from the state of massachusetts.
The goal is get this cleaned up and then use it as a basis for driving the gun demographics test and then use that to rationalize gun spawns.

Describe the solution

Importing this data needs to be a process, not a one-off task, because next year there may be a new archive available that we would want to append to, and I don't want tanyone to have to reeat the hours of work I've put into figuring out how to rationalize this.

Describe alternatives you've considered

Just not doing it and have made up gun demographics?
Really sloppy data import?
Reinvent the wheel next year?

Testing

The output is pretty much someone else attempting to follow the process.

[kevingranade]

This wasn't done, but it shouldn't hurt to have it in.