optimizations (#2904)

* calc once, then re-use
* prevent invalid theme switch
* allow to turn off weekly-quick-entries by permissions
* remove 00:00 from date-times that likely do not need a time
* fix datepicker out of window

assets/js/plugins/KimaiDateTimePicker.js

@@ -37,6 +37,7 @@ export default class KimaiDateTimePicker extends KimaiPlugin {
                 timePicker24Hour: is24hours,
                 showDropdowns: true,
                 autoUpdateInput: false,
+                drops: 'down',
                 locale: {
                     format: localeFormat,
                     firstDay: firstDow,
@@ -50,7 +51,8 @@ export default class KimaiDateTimePicker extends KimaiPlugin {
 
             jQuery(this).on('show.daterangepicker', function (ev, picker) {
                 if (picker.element.offset().top - jQuery(window).scrollTop() + picker.container.outerHeight() + 30 > jQuery(window).height()) {
-                    picker.drops = 'up';
+                    // "up" is not possible here, because the code is triggered on many mobile phones and the picker then appears out of window
+                    picker.drops = 'auto';
                     picker.move();
                 }
             });