First release of gpac

Release changes

Base gpa calculator (gpac) CLI completed, users are now able to:

• initialise gpac with the subcommand gpac init
• add module information (module code, module units and module grades) with the subcommand gpac add
• list module information with the subcommand gpac list
• update module information of given module code with the subcommand gpac update
• remove module information of given module code with the subcommand gpac remove
• simulate applying S/U options to different modules with the subcommand gpac simulate
• calculate the simulated GPA (GPA after simulating the application of S/U options to different modules) and actual GPA with the subcommand gpac gpa