Create view for code_status in MIMIC-IV

[ajb5d]

Create a new view with code status orders for MIMIC-IV data:

• Started with mimic-iii/concepts/code_status.sql
• Changed icustay_id references to stay_id
• Removed carevue specific itemid and logic (DNCPR)

[alistairewj]

Thanks - I changed it from first/last/max to just time/code status, which is more consistent with the MIMIC-IV style of views. Very easy for everyone to grab the first/last row per patient this way.

I also added in code status from the poe table, which is a new addition in MIMIC-IV. These are hospital wide orders, so code status changes from outside the ICU should now be incorporated.