Mwrpy

- Update lev2 quality flags and attributes
- Change lev2 indexing to allow combining products retrieved with different elevation angles
- Update thresholds for spectral retrieval

- Use tempfiles

- Optimize bit handling in level 2 processing

- Fix package exports

- Add flags to level 2 products
- Exclude scans in LWP offset correction
- Fix many warnings and typing issues

- Fix `ir_zenith_angle` variable metadata