Add import_and_save function to be used with Celery.
Add import_and_save function to be used with Celery.

  * Add new function to be used as an external task with Celery
    so that job import is executed outside of the web server.
  * Fixed return values of import functions.

kernelci/kernelci-backend,joyxu/kernelci-backend,joyxu/kernelci-backend,joyxu/kernelci-backend,kernelci/kernelci-backend