Integrate firebase auth with google calendar

[a-paggabao]

• Add Firebase config, which is safe to publish according to a firebase dev.

• Add Google Calendar API

• Add functionality for user to sign in with their Google account

• Add functionality for user to synchronize all of their Google Calendars

• Add functionality for user to get all Calendar Events based on selected calendars

• Add State Store for user's calendar list

• Add tests (other than 'should create') for:

  • google-calendar.component
  • calendar-list-store.service