Add residence history

This branch does the following Good Things:

- Mostly fixes #117: You can enter a residence history
- Breaks up the main form into multiple smaller forms, allowing submittal from different parts of the form to go to different controllers
- Adds a big red "Delete" button for deleting residence entries and household members, replacing the weird little checkbox
- Reorganizes much of the database schema, putting us in a better position to tackle #108

Here are some problems with it:

- Since there are multiple forms instead of the one giant form, whatever progress was made towards #113/#120 no longer works as intended, sorry about that
- You still can't reuse an address, because I'm not sure how the form should support editing the same address from multiple places

But all in all, I'd say it's a step forward.