Add a flowsheet fixer feature to FEMR

[EthanSteinberg]

FEMR v1 had a very useful feature where it would normalize flowsheet values: https://github.com/som-shahlab/femr/blob/b8d7d25154166a82e293c11bd2c1e1ef9160c11b/tools/stanford/flowsheet_cleaner.py

It would be good if someone can port this over to V2 to make flowsheets easier to process.