Find new way to display five or more sessions of data on a legislator page

[dscush]

On each legislator page, we currently show the current and previous two sessions' scorecards, for three total. The way it's displayed in tabs has a good spacing right now. We should be able to squeeze a fourth in there but it might look a bit tight. Adding a fifth two years from now will be an issue, so we need to think about how we want to rearrange that part of the UI.

This is not urgent. We have two years to solve it.