Add favicon.ico endpoint

Closes #1121

app/routes.py

@@ -595,7 +595,7 @@ def window():
     )
 
 
-@app.route(f'/robots.txt')
+@app.route('/robots.txt')
 def robots():
     response = make_response(
 '''User-Agent: *
@@ -604,6 +604,11 @@ Disallow: /''', 200)
     return response
 
 
+@app.route('/favicon.ico')
+def favicon():
+    return app.send_static_file('img/favicon.ico')
+
+
 @app.errorhandler(404)
 def page_not_found(e):
     return render_template('error.html', error_message=str(e)), 404