fix metno caching and dpird old vs new schema

[bozaah]

This pull request adds caching and conditional revalidation for MET Norway (MET.NO) weather forecast API calls. It introduces new options to control cache usage, cache directory, and fallback to stale data on rate limits.

MET Norway forecast caching and updates:

• Added session-scoped caching to get_metno_forecast() and get_metno_daily_forecast(). Also added conditional revalidation using response headers (If-Modified-Since and handling of HTTP 304 Not Modified and 429 rate limit). Added new arguments use_cache, cache_dir, and allow_stale_on_error to MET.NO functions.

Bug fixes:

• Fixed .parse_summary() to combine paginated get_dpird_summaries() responses with mixed schemas, filling missing fields with NA instead of erroring during row binding.

Documentation updates:

• Updated NEWS.md and documentation to describe the new caching features, wind data structure changes, and improvements to the MET Norway forecast integration.