Some fix for PHP 7,2 https://github.com/osTicket/osTicket/issues/4237

This is important to show custom statuses with properties.

Add a preview tool tip to show list item properties on mouse-over.

Previously, the create method was used to create a new instance of an orm
model (which would later result in an INSERT when persisted); however, some
classes require or utilize varying parameters to their create() method,
which PHP7 considers an error. Methods in subclasses must be defined with a
calling signature compatible with the parent class.

This patch shifts the concept of model creation to the constructor. Now, the
constructor of ORM models is required to be compatible with that of
ModelBase class. Now that most models do not define a constructor, this is
much easier to control, and much more logical.

Also, remove an issue where assignments on a relationship field to an
instance of a super class of the foreign model would raise an error. This
was previously addressed by re-classing the instance in the
ModelInstanceManager::getOrBuild(); however that design would create
multiple instances of the same object in memory, which defeats one of the
primary design concepts of the ORM. This patch addresses the issue by
allowing super-classes of the declared foreign model in relationship
assignments.

Use CsvImporter util to importing items
Fix items search

Allow fields to internally define the render mode. This allows for fields to
to self render in a view mode when it's not editable.

Allow changing/saving setting/properties on internal ticket statuses. With
the exception of the state.

Fixes #2328

This patch shores up the new list management feature with the custom list
handler feature written to support lists being saved in a table other than
%list_item, namely the built-in ticket status list.

Also squelch the 'You sure?' popup appearing multiple times.

This adds ability to delete properties on list deletion

This is a temporary patch for v1.9.7 -- develop-next already has a better
implementation.

Add ability to import and export list items

Support using value or abbrv. for choice/selection input fields.

Add order by method to ticket status list to return appropriate sort columns
Delegate __get method in CustomListHandler to the parent list

This will allow administrator to indicate if end users are allowed to reopen
tickets in a particular closed status.

And allow for @context to add context to the bare string literal. For
instance,

    /* @trans, @context "noun" */ 'Open'

Would mark the string 'Open' translatable with context "noun".

Always save a key/value hash of the selected value(s). However, if the field
does not have the multivalue configuration setting, then retrieve just the
key with the to_php() function. to_database(), however, will always return a
JSON string with the value(s) formatted as a hash array.

Statuses with tickets cannot be deleted
Fix orm to class gracefully when joins are not inspected
Add create date to new statuses