Add Sky Culture Feature

[AndyTza]

Is your feature request related to a problem? Please describe.
Starplot currently only supports IAU-recognized constellations and names in its database. As a user, I want to create constellation maps that reflect the names and line patterns from other parts of the world, such as those used in Hawai'i. The current API does not easily support the integration of custom constellation systems.

Describe the solution you'd like

1. Add a SkyCulture parameter to constellation methods. Implement a built-in sky culture feature that allows users to specify different cultural constellation systems. For example:

p = MapPlot(
    projection=Projection.ZENITH,
    lat=15.153414,
    lon=-116.83123,
)
p.constellations(SkyCulture='Hawaii')

2. Add a tutorial explaining how users can customize and add their own constellation systems, including documentation, data format requirements and file structure, and integrating with the current API.

Describe alternatives you've considered
I tried adding a few new stars to src/starplot/data/constellations.py, constellation_stars.py, and constellation_lines.py, but I couldn't get it to work.

Additional context

This feature would be awesome and would significantly expand Starplot's accessibility by supporting multiple astronomical naming systems. I think the main challenge lies in identifying reliable data sources for star names, constellation boundaries, and line patterns across different regions. Stellarium currently has a nice Sky Culture feature (see screenshot), but I wonder if this could be a starting point to scrape all the constellation names, stars, and constellation lines.

[steveberardi]

I'd love to add built-in support for more sky cultures! I see it working just as you described with a kwarg on the constellations function (similar to specifying star catalogs when plotting stars). To implement this, I'll need to re-organize some of the constellation data but that should be fairly easy.

As far as data sources, Stellarium does have a repo for all their sky cultures -- https://github.com/Stellarium/stellarium-skycultures -- it looks like everything is in a standard format too. We'd just have to confirm each one we use has an open license.

Anyway, I'll add this to the roadmap. Thanks for the suggestion!