Added some error handling to the Project Samples page

* `console.log` calls when any of the AJAX calls fail
* **Project Not Found** page display when no project is returned, instead of just an empty template
  * _eg._ https://genomics-status-stage.scilifelab.se/project/this_project_doesn't_exist
* **No Samples Found** in the samples tab instead of an empty table if no samples..
  * _eg._ https://genomics-status-stage.scilifelab.se/project/P920
Yup - or just use `Object.getOwnPropertyNames(data).length == 0` only, which is what I went for. If the project isn't found it returns an empty project which satisfies both of the first two anyway. I can't think of any circumstances where we'd get an null or undefined object returned.