Return monthly data with months as integers rather than abbreviated strings

[GUI]

Feedback from our API Usability Testing: In the solar resource output, we return monthly data as an object where the keys are month abbreviations (eg, "jan", "mar"). It was suggested that we use integers for months instead (so 1-12), which is a little more universal, and also makes things easier to sort on or iterate through.

[reger]

This was because the original python service returned the data that way.

[GUI]

Yeah, I don't think we can necessarily make changes like this in any of our existing APIs due to backwards compatibility issues, but I think this would be a good thing to generally discuss the next time we're releasing a new version or a new API that deals with months.