Auth forms fix (#3214)

* Improvement and consolidation of various auth forms

* Update "disable 2FA" page to use form fields

Note: Requires merging of https://github.com/valohai/django-allauth-2fa/pull/135

* Update django-allauth-2fa requirements

InvenTree/templates/allauth_2fa/authenticate.html

@@ -9,7 +9,7 @@
   {{ form|crispy }}
 
   <button type="submit" class="btn btn-primary">
-    {% trans 'Authenticate' %}
+    <span class='fas fa-check-circle'></span> {% trans 'Authenticate' %}
   </button>
 </form>
 {% endblock %}