[Progress] Event Detail Page implemented

[njs03332]

Done:

• Event info: shows event information (name, date, content)
• Future attendance check: If a member checks whether he/she will attend the event, the member is shown on the list. You can also change whether you will attend the event or not.
• Past attendance check: A checkbox list of members is shown and if you check the attended members and submit, the list is shown.
• permission: only admin can check past attendance
• for future event, only FutureAttendance component is shown
• for past event, not able to change future attendance (only viewing the future attendance list is available)

Todo:

• delete / edit event
• Event Statistics Front end needs to be implemented