Create api endpoint for User

[kehwhy]

Create a user with the POST endpoint
An example of the REST endpoints - https://github.com/hack4impact-mcgill/mu-crm-tool/blob/main/backend/app/project/routes.py

More info on REST api endpoints: https://www.restapitutorial.com/lessons/httpmethods.html

[peterghrong]

Users have fixed passwords, you might want to think about how you'd want to store the fixed hashed strings. One valid approach might be adding the hashed string to the env file and have api do hashing and valid with the env file.