Update DOM display and class properties after 'post' or 'delete'

[hfaerber]

Not explicitly stated in the rubric bullet points but important for UI/UX.

My DOM displays should be updated whenever a new booking is posted or deleted.

Update would happen in each class first then the updates would be displayed.

Affected displays:
GUEST
Total spent (loyalty points)
List of bookings

MANAGER
Selected guest's displayed rooms and loyalty points
All 3 below depending on whether booking is for today.
Occupancy (depending on date booked for)
Revenue
Availability (depending on date booked for)