Safety is horrible

[fretchen]

Describe the bug
I ran the website through the mozilla Observatory and we had a score of 0/100:

https://observatory.mozilla.org/analyze/devicecontrolserver.herokuapp.com

[fretchen]

Once could add flask-talisman, but for that it is necessary to kill out the bootstrap first. However, this might not be the biggest issue as flask-bootstrap seems to be rather poorly maintained anyway.