Remove business_logic_teams

The middleware/business_logic_teams.py file does not appear to be necessary. It is used to validate that the input to generate a team does not break uniqueness constraints. This should be handled by the database and should be returned to the user through proper exception handling. Research into if there is any actual value in this file should be conducted. If necessary, database constraints should be created as appropriate and the file should be removed if it doesn't provide any real value.