Fix #3228 - UrlEncode full path for next if not on logon page

Include the full path for the ?next= variable in login links if we are not on the logon page.
Additionally include next for post requests that have the next variable set (will only come from the login page itself generally)

netbox/templates/inc/nav_menu.html

@@ -413,7 +413,12 @@
                         </ul>
                     </li>
                 {% else %}
-                    <li><a href="{% url 'login' %}?next={{ request.path }}"><i class="fa fa-sign-in"></i> Log in</a></li>
+                    {% url 'login' as login_url %}
+                    {% if request.path == login_url %}
+                        <li><a href="{{ request.get_full_path }}"><i class="fa fa-sign-in"></i> Log in</a></li>
+                    {% else %}
+                        <li><a href="{{ login_url }}?next={{ request.get_full_path | urlencode }}"><i class="fa fa-sign-in"></i> Log in</a></li>
+                    {% endif %}
                 {% endif %}
             </ul>
             <form action="{% url 'search' %}" method="get" class="navbar-form navbar-right" id="navbar_search" role="search">

netbox/templates/login.html

@@ -25,6 +25,7 @@
                 <div class="panel-body">
                     {% csrf_token %}
                     {% if 'next' in request.GET %}<input type="hidden" name="next" value="{{ request.GET.next }}" />{% endif %}
+                    {% if 'next' in request.POST %}<input type="hidden" name="next" value="{{ request.POST.next }}" />{% endif %}
                     {% render_form form %}
                 </div>
                 <div class="panel-footer text-right">