delete obsolete requirements and add a confirmation step before deleting users in /users view

requirements.txt

-# Versions from Debian Buster
-ldap3==2.4.1
-flask==1.0.2
-Flask-SQLAlchemy==2.1
-qrcode==6.1
-fido2==0.5.0
-Flask-OAuthlib==0.9.5

uffd/user/templates/user.html

@@ -8,7 +8,7 @@
 		<a href="{{ url_for("user.index") }}" class="btn btn-secondary">Cancel</a>
 		{% if user.uid %}
 			<a href="{{ url_for("mfa.admin_disable", uid=user.uid) }}" class="btn btn-secondary">Reset 2FA</a>
-			<a href="{{ url_for("user.delete", uid=user.uid) }}" class="btn btn-danger"><i class="fa fa-trash" aria-hidden="true"></i> Delete</a>
+			<a href="{{ url_for("user.delete", uid=user.uid) }}" onClick="return confirm('Are you sure?');" class="btn btn-danger"><i class="fa fa-trash" aria-hidden="true"></i> Delete</a>
 		{% else %}
 			<a href="#" class="btn btn-danger disabled"><i class="fa fa-trash" aria-hidden="true"></i> Delete</a>
 		{% endif %}