Expose the map of resolved widget properties in widget templates variables

For select2 widgets, the map of resolved widget properties is needed to convert it to a map of properties that is given to the select2 javascript code.

When retrieving properties directly on the widget, properties that are referencing EL expressions are not resolved, and they need to be resolved in the context of the page being rendering to have access to all render variables (typically, the js code that enables checking the radio button when typing on the field on the bulk edit layout).

The easiest would be to convert propeerties from a map of already resolved properties, so let's add it to the context when rendering a template widget type.