WP-306 draft schemas for climate trace outputs

[HughRunyan]

Pairs with #55 in RMI Climate TRACE repo.

The changes are mostly hardcoded values for constants, cleaning up the handling of modeling time window.

[andre-scheinwald]

Seems pretty straight forward. Replacing hardcoded values everywhere with a single constant from another repo.

I have 1 suggestion. I noticed you have MODEL_END_YEAR + 1 everywhere in city_params because you're using range. Makes sense. I think it would be beneficial here to have a global variable outside the funcs. Something like:

MODEL_END_YEAR_PLUS_1 = MODEL_END_YEAR + 1

And then replace every instance of MODEL_END_YEAR + 1 with the global var.
This way if you ever have to tweak this you only have to change it on one line. Vs. every line it shows up in.
Up to you if this makes sense or not.

Saw there's a merge conflict, good luck!