message: chore(backend): update firebase ruls for markers
diff: rules_version = '2';
  function verifyMarkerDataComplete(data) {
  - return ('contentTitle' in data) &&
  + return data.visible == false &&
  + ('contentTitle' in data) &&
  ('type' in data) &&
  ('type' in data.type) &&
  ('contact' in data) &&
  ('loc' in data) &&
  ('description' in data.loc) &&
  - ('lat' in data.loc) &&
  - ('lng' in data.loc) &&
  + verifyLatLngObject(data.loc.latLng) &&
  ('serviceRadius' in data.loc)
  }
  