- getSeason() only for staff members

- new view staff()
- updated bootstrap to version 3.4.1
- updated jquery to 3.6.3
- changed container layout in main view 'matchday'

templates/nav.html

@@ -16,6 +16,9 @@
           <li><a href="/">Tipps</a></li>
           <li><a href="/charts/{{ ls }}/{{ season }}{% if pos %}/{{ pos }}{% endif %}">Bestenliste</a></li>
           <li><a href="/blog/1">Blog</a></li>
+          {% if request.user.is_active and request.user.is_staff %}
+              <li><a href="/staff">Staff</a></li>
+          {% endif %}
         </ul>
         <ul class="nav navbar-nav navbar-right">
           {% if has_refresh %}