Fix now indicator in fullcalendar views (AKPlan) for users from other timezones

• This is done by generating the "now" timestamp from python instead of JavaScript using a newly created templatetag
• The new "now" function is used in all AKPlan calendar views as well as in AKScheduling's scheduler view

AKPlan/templates/AKPlan/plan_akslot.html

 {% load static %}
 {% load tz %}
 {% load i18n %}
+{% load tags_AKPlan %}
 
 {% include "AKPlan/load_fullcalendar.html" %}
 
@@ -27,6 +28,7 @@
             scrollTime: '08:00:00',
             allDaySlot: false,
             nowIndicator: true,
+            now: "{% timestamp_now event.timezone %}",
             eventTextColor: '#fff',
             eventColor: '#127ba3',
             // Create entries for all scheduled slots