Add CLI and ListIO class

.gitignore

build.gradle

gradle/wrapper/gradle-wrapper.jar

gradle/wrapper/gradle-wrapper.properties

gradlew

gradlew.bat

settings.gradle

src/main/java/softeng/g4/Main.java

src/main/java/softeng/g4/appointment/Appointment.java

src/main/java/softeng/g4/appointment/Reminder.java

src/main/java/softeng/g4/appointment/RequestAppointment.java

src/main/java/softeng/g4/calendar/Calendar.java

src/main/java/softeng/g4/calendar/Schedule.java

src/main/java/softeng/g4/cli/AdminCLI.java

src/main/java/softeng/g4/cli/ListIO.java

src/main/java/softeng/g4/cli/StudentCLI.java

src/main/java/softeng/g4/cli/TACLI.java

src/main/java/softeng/g4/course/Course.java

src/main/java/softeng/g4/course/CourseList.java

src/main/java/softeng/g4/courselist.txt