Removed asterisk from record contact details heading
Added asterisks to subheadings to help users
understand what needs to be filled out.
(better user experience)

when user selects contact type on new contact page

- modified '_contact_types.html.erb' to sort by last_contact_time
- updated ContactTypeDecorator with last_contact_timestamp method
to obtain last contact or default to a time in past if no contacts

Change was made in order to ensure that 'ContactType' options are
displayed for users in a way that allows them to quickly access
recently used contact types vs scrolling through all options.

Added server side validation to the contact model
in order to ensure that "Contact Type" is filled
out as required field when user submits a new case
contact details form