Added 'status' to the Listing

When creating a new Listing, the status of the Listing is set to
‘Active’.

When editing a Listing, the status can be changed to ‘Active’,
‘Pending’, or ‘Closed’.
Added UIScrollView to Listing Detail View
Added constraints to views

Added scrollviews and constraints to the views for posting a listing,
viewing a listing, and editing a listing.

Did a few other small things including cropping the profile image to a
circle, listing conversation and ‘My Items’ in reverse order to reflect
the most recent first, etc.