feat: Add mimic-iv-note (v2.2) loading of postgres

[DopamineLcy]

Add mimic-iv-note (v2.2) loading method of postgres, thank you!

[DopamineLcy]

BTW, if I add the constraint of "hadm_id" in "radiology" NOT NULL, an error will occur, which is not consistent with https://mimic.mit.edu/docs/iv/modules/note/radiology/, maybe the data should be checked.
So I remove the NOT NULL constraint of "hadm_id" in "radiology".
Thank you very much.

[alistairewj]

This looks great, thank you! Going to merge this in and update any data types that may have changed since we described the data on the website (including the NOT NULL constraint like you noted).