set kernel priorities

[williamstein]

E.g., for sage it is 1 but should be 10:

/usr/local/share/jupyter/kernels/python3-ubuntu$ more ../sagemath/kernel.json 
{
  "display_name": "SageMath",
  "argv": [
    "sage",
    "--python",
    "-m",
    "sage.repl.ipython_kernel",
    "--matplotlib=inline",
    "-f",
    "{connection_file}"
  ],
  "language": "sagemath",
  "metadata": {
    "cocalc": {
      "priority": 10,
      "description": "Open-source mathematical software system",
      "url": "https://www.sagemath.org/"
    }
  }
}

None of the others are set at all. Code in cocalc works better assuming these are set.