Update outcomes, add script for ICD codes, update load function

[mlondschien]

• Added outcomes: severe respiratory failure at 24h, meld score in 24h, log(creatinine) in 24h.
• The (severe) respiratory failure definition varies by dataset. For NWICU, PICdb, Zigong, where p/f is rarely available, the event is defined via sao2 <= 90
• For PICdb and Zigong, where map is not or only very sparsely available, a negative circulatory failure event no longer requires a non-missing map >= 65.
• The "normal urine rate" condition is no longer required for negative labels of kidney failure.
• I added a script to compute / transform ICD10 codes. This is very specific to my use-case. Should we leave this as is, incorporate this into the features.py, or move it to a separate branch?
• restructured polars computation to require less memory