new jquery based widgets for Time/Date/DateTime, backported from crm

introduce a default render implementation on the base widget, which add_media and then call the newly introduced method _render(form, field, formrenderer), abstract of the base widget class. This allow a litle code factorisation and avoid to forget the call to add_media in subclasses.

[forms] new optional suffix attribute on widget objects, used to generage input name / dom id. Ease reuse of widgets from another widget. Also move base values computing to a separated values(form, field) method.

introduce new _ensure_correctly_typed method on fields, responsible to ensure the value return by the widget is suitable for that kind of field. Also factorize date and time fields.

fix typed_value implementation w/ eidparam field which are actual entity's relation and have .value set for their initial value

cleanup module namespace but only importing the formwidgets module

fix deprecation warnings

fif inlined relation forms pb w/ new ajax forms. We've to ensure the varmaker is properly initialized when generating a form where we may add new subentities, which will use ajax call to generate the subform while this subform expect a varmaker to be set.