Fix position to reflect start and end date

[ethanrossblack]

PROBLEM

Currently, each position object is from a lobbyist's monthly report. That means that if a client's position on a bill hasn't changed from one month to the next, there's essentially duplicate data for that position.

I need to come up with a way to consolidate these identical positions.

---

Right now, a position's "position" is a string that usually looks like the following:

Monitoring 01/15/2024 to Ongoing

A typical, single position has the following attributes

1. Position
2. Start date
3. End date, which can either be a concrete date or "Ongoing"