- Reset the app idle timer when interacting with the webapp, so that the
  device does not turn off while the web ui is used.

- Handle denying put/post while playback is active centrally in the
  before_request handler, so that it does not need to be copy/pasted
  into every request handler.

Signed-off-by: Matthias Blankertz <matthias@blankertz.org>

@@ -62,0 +71,4 @@
+@webapp.route('/api/v1/last_tag_uid', methods=['GET'])
+async def last_tag_uid_get(request):
+    tag, _ = nfc.get_last_uid()
+    return "No tag present" if tag is None else tag