Add /spaces functionality

[chikchengyao]

Add "/spaces" command, displaying bookings of Spaces in Cinnamon active on the same day.

Optional arguments:

• "/spaces now", displaying bookings active at that moment,
• "/spaces week", displaying bookings in the next 7 days,
• "/spaces dd/mm/yy", displaying bookings on a particular date, and
• "/spaces dd/mm/yy dd/mm/yy", displaying bookings in a particular date range.