Create argparse CLI option for password manipulation

[DangaRanga]

• Allow for the generation and reseting of passwords
  • When resetting passwords just prompt for the new password to be created
• Place function for password manipulation under pattoo.db.user.py
  • get_password and set_password could be the function names
• Ensure the permissions are 700 so that only the owner of the repository and the root can run it
• Possibly use SHA-512
• Write unittests to:
  • check if the user associated with the password already exists in the database
  • Ensure that the password can be recreated based on the salt that's in the database