Add solar position for PV-sites

[jacobbieker]

Pull Request

Description

Adds PV site solar elevation and azimuth, not just GSP.

Fixes #

How Has This Been Tested?

Unit tests

• [ ] Yes

Checklist:

• [ ] My code follows OCF's coding style guidelines
• [ ] I have performed a self-review of my own code
• [ ] I have made corresponding changes to the documentation
• [ ] I have added tests that prove my fix is effective or that my feature works
• [ ] I have checked my code and corrected any misspellings

[codecov[bot]]

Codecov Report

Attention: 2 lines in your changes are missing coverage. Please review.

Comparison is base (ae1d46b) 56.99% compared to head (74aae2b) 56.99%. Report is 1 commits behind head on main.

Files	Patch %	Lines
pvnet/models/base_model.py	0.00%	2 Missing :warning:

Additional details and impacted files

```diff @@ Coverage Diff @@ ## main #131 +/- ## ======================================= Coverage 56.99% 56.99% ======================================= Files 28 28 Lines 1795 1795 ======================================= Hits 1023 1023 Misses 772 772 ```

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