[REM] Remove inheritance on DateTimeWidget

The inheritance of the start function is not needed, because
the function is already inherited from DateWidget.

web_widget_datepicker_options/static/src/js/datepicker.js

@@ -24,24 +24,8 @@ odoo.define('web_widget_datepicker_options', function (require) {
 
     var core = require('web.core');
 
-    var DateTimeWidget = require('web.datepicker').DateTimeWidget;
     var DateWidget = require('web.datepicker').DateWidget;
 
-    DateTimeWidget.include({
-        start: function(parent, options) {
-            this._super.apply(this, arguments);
-            var self = this;
-            if (this.__parentedParent.options.datepicker) {
-                var options = this.__parentedParent.options.datepicker;
-                $.each(options, function(value, key) {
-                    self.options[value] = key;
-                    self.picker[value] = key;
-                    self.picker.options[value] = key;
-                });
-            }
-        },
-    });
-
     DateWidget.include({
         init: function(parent, options) {
             this._super.apply(this, arguments);