Pv prod fix

[adfarth]

Please check if the PR fulfills these requirements

• CHANGELOG.md is updated
• Tests for the changes have been added (for bug fixes / features)
• [N/A ] Docs have been added / updated (for bug fixes / features) --> @NLaws do you think we should update the user manual for this?

What kind of change does this PR introduce?

(Bug fix, feature, docs update, ...)

• In src/pvwatts.py, Updated lat-long coordinates if-statement used to determine whether the "nsrdb" dataset should be used to determine the PV prod factor. Accounts for recent updates to NSRDB data used by PVWatts (v6)
• Avoids overwriting user-entered PV azimuth (other than 180) for ground-mount systems in southern hemisphere
• Updates default azimuth to 0 for southern latitudes for all PV types (rather than just for ground-mount)

What is the current behavior?

(You can also link to an open issue here)

• Incorrect bounds of NSRDB dataset are applied in PVWatts API call, meaning we are using lower quality PV resource data for some international sites
• Default azimuth remains at 180 for rooftop systems in southern hem
• Overwrites user-entered PV azimuth for ground-mount systems in southern hemisphere

What is the new behavior (if this is a feature change)?

See changes

Does this PR introduce a breaking change?

(What changes might users need to make in their application due to this PR?)
Yes? More accurate PV data will be used for international evaluations.

Other information:

These are the bounds that are now applied to the NSRDB query:

[NLaws]

A couple comments to address but looks good!

Can we combine your new test with this old one:
https://github.com/NREL/REopt_API/blob/master/reo/tests/test_southern_hemisphere_latitude.py
?
Combining the two would make one less API post/optimization in the test suite.

[adfarth]

A couple comments to address but looks good!

Can we combine your new test with this old one: https://github.com/NREL/REopt_API/blob/master/reo/tests/test_southern_hemisphere_latitude.py ? Combining the two would make one less API post/optimization in the test suite.

Combined these tests here! 9eb58aa

[NLaws]

Please merge if tests pass. We can also merge this into master after testing the develop deploy and merge to staging/production thereafter.