feat: Refactor template handling, improve scheduler functions, and add timezone utilities

- Moved Jinja2 template setup to a shared configuration file (templates_config.py) for consistent usage across routers.
- Introduced timezone utilities in a new module (timezone.py) to handle UTC to local time conversions and formatting.
- Updated all relevant routers to use the new shared template configuration and timezone filters.
- Enhanced templates to utilize local time formatting for various datetime fields, improving user experience with timezone awareness.

templates/partials/projects/unit_list.html

@@ -60,7 +60,7 @@
                         {% if item.assignment.assigned_at %}
                         <div class="col-span-2">
                             <span class="text-xs text-gray-500">Assigned:</span>
-                            <span class="ml-1">{{ item.assignment.assigned_at.strftime('%Y-%m-%d %H:%M') }}</span>
+                            <span class="ml-1">{{ item.assignment.assigned_at|local_datetime }}</span>
                         </div>
                         {% endif %}
                     </div>