ENH: cache downloaded atmosphere netCDF datasets (#654)

[thatrandomasiandev]

Summary

• Cache Forecast/Ensemble (and Reanalysis remote URLs) location-time profiles as compact .nc files under ~/.rocketpy_cache/atmosphere (override with ROCKETPY_CACHE).
• Cache Windy JSON responses on the same path; second identical set_atmospheric_model calls reuse disk.
• Add no_cache=False to Environment.set_atmospheric_model (and Windy processing) so callers can force a fresh download without breaking existing callers.

Notes / TODOs

OPeNDAP "Best" aggregations are virtual catalogs, not downloadable files, so this PR caches the extracted profiles RocketPy already materializes after the first fetch (same end-user outcome: reruns skip the network). Remaining follow-ups:

• Open-Meteo / Meteomatics JSON response caching
• Optional full-file download cache when a remote source is a concrete HTTP .nc (non-OPeNDAP)

Fixes #654

Test plan

• PYTEST_DISABLE_PLUGIN_AUTOLOAD=1 pytest tests/unit/environment/test_atmosphere_cache.py
• Confirm Forecast shortcut reuses disk on rerun with same lat/lon/date
• Confirm no_cache=True forces re-download