feat: ✨ adding schedule meeting logic

[amhaiskar0921]

Features added

• A new availability view where users can see everyone's availability and schedule a meeting by selecting a contiguous block of time in a single day. Selection is golden colored.
• Cancel button that resets the current selection and takes the user back to the group availability view
  • If a meeting is scheduled and the user is attempting to edit it, then pressing cancel resets it back to the original scheduled time block
• Save button that saves the current time selection to the meetings database
  • Schema change: meetings table now has scheduledFromTime, scheduledToTime, and scheduledDate columns
  • The currently scheduled time block shows up in golden each time the meeting is opened
  • If a user is editing the scheduled time, then saving overrides the original date/time with the new date/time
• Summary page updates
  • 2 tabs showing scheduled and unscheduled meetings separately (existing component in meetings.tsx that was uncommented)
  • New features:
    • Scheduled meetings now show their scheduled date and scheduled from/to times in the summary page
• Google calendar integration (partially done), which opens the meeting with its title in Google Calendar

Next steps

• Complete Google Calendar integration
• Scheduling recurring meetings across multiple days (could be at different times each day)
• Scheduling a single meeting on multiple days (could be at different times each day)
• Clean up calendar component / UI
• Event handlers for mobile devices may need changes

Closes #191