Calendar for Availabilities Input

[jduong09]

Feature

• Add Calendar for user to select whole days as meeting days instead of selecting time blocks.
• Closes #20

[jduong09]

Update

• Added MonthlyCalendar, which displays a calendar with no times, only the days in the month.
• User can select which days they want to meet.
• Added ability to toggle between meeting for times, and meeting for a day.
• Currently, choosing to meet for times will not allow to meet for a day, and vise-versa.
• Manipulated how duration is sent to frontend on the backend side.
• Added active states for visibility/testing purposes. Current design is not the final design.