Add missing Python libraries for Flask

[krivard]

in: https://github.com/cmu-delphi/operations/blob/main/dev/docker/python/assets/requirements.txt

add: python-dotenv, flask, orjson, sqlalchemy==1.3.24, others?

ref: cmu-delphi/delphi-epidata#417 (comment)

[sgratzl]

see https://github.com/cmu-delphi/delphi-epidata/blob/main/requirements.txt and https://github.com/cmu-delphi/delphi-epidata/blob/main/requirements.dev.txt