Create gallery page for shifts_ruptures

[kandersolar]

• [ ] Closes #xxx
• [ ] Added tests to cover all new or modified code.
• [ ] Clearly documented all new API functions with PEP257 and numpydoc compliant docstrings.
• [ ] Added new API functions to docs/api.rst.
• [ ] Non-API functions clearly documented with docstrings or comments as necessary.
• Adds description and name entries in the appropriate "what's new" file
  in docs/whatsnew
  for all changes. Includes link to the GitHub Issue with :issue:`num`
  or this Pull Request with :pull:`num`. Includes contributor name
  and/or GitHub username (link with :ghuser:`user`).
• Pull request is nearly complete and ready for detailed review.
• Maintainer: Appropriate GitHub Labels and Milestone are assigned to the Pull Request and linked Issue.

I made an example script for shifts_ruptures for someone else and thought might as well clean it up and add it to the gallery too.

[kandersolar]

@kperrynrel, might you be interested in reviewing this PR? This is my first time using this function and it would be helpful to check that this usage is appropriate for an example. No rush at all of course :)

Rendered version here: https://pvanalytics--192.org.readthedocs.build/en/192/generated/gallery/data-time-shifts/shifts-ruptures.html

[kperrynrel]

Apologies on this taking forever for a response, the past month or so has been pretty hectic and I just started going back through PR's. I'm a little torn, and I want your opinion: the logic currently existing here is adapted from Fleets, but it's not the same as the finalized functions that I'm planning on piping over (which were validated at PVRW). Should we keep the ruptures shift functions in here, or deprecate them once we get the new functions in place? BTW I haven't tested anything that's currently sitting the package.

[kperrynrel]

@kandersolar added the new get_sunrise and get_sunset functions from #187 into the example and it ran successfully:

[kandersolar]

Docs build looks good. Test errors aren't relevant here, so I'll go ahead and merge. Thanks @kperrynrel for taking a look!