Re-raise Kubernetes exceptions as HttpError

[TomAugspurger]

Here's the CLI output now:

❯ kbatch job submit --name=TEST --image="alpine"
[14:22:15] ERROR    {'detail': '{"kind":"Status","apiVersion":"v1","metadata":{},"status":"Failure","message":"Job.batch \\"TEST-6c6wr\\" is invalid: [metadata.generateName: Invalid value: \\"TEST-\\": a DNS-1123 subdomain must consist of lower case         _core.py:226
                    alphanumeric characters, \'-\' or \'.\', and must start and end with an alphanumeric character (e.g. \'example.com\', regex used for validation is \'[a-z0-9]([-a-z0-9]*[a-z0-9])?(\\\\.[a-z0-9]([-a-z0-9]*[a-z0-9])?)*\'), metadata.name:
                    Invalid value: \\"TEST-6c6wr\\": a DNS-1123 subdomain must consist of lower case alphanumeric characters, \'-\' or \'.\', and must start and end with an alphanumeric character (e.g. \'example.com\', regex used for validation is
                    \'[a-z0-9]([-a-z0-9]*[a-z0-9])?(\\\\.[a-z0-9]([-a-z0-9]*[a-z0-9])?)*\')]","reason":"Invalid","details":{"name":"TEST-6c6wr","group":"batch","kind":"Job","causes":[{"reason":"FieldValueInvalid","message":"Invalid value: \\"TEST-\\": a
                    DNS-1123 subdomain must consist of lower case alphanumeric characters, \'-\' or \'.\', and must start and end with an alphanumeric character (e.g. \'example.com\', regex used for validation is
                    \'[a-z0-9]([-a-z0-9]*[a-z0-9])?(\\\\.[a-z0-9]([-a-z0-9]*[a-z0-9])?)*\')","field":"metadata.generateName"},{"reason":"FieldValueInvalid","message":"Invalid value: \\"TEST-6c6wr\\": a DNS-1123 subdomain must consist of lower case
                    alphanumeric characters, \'-\' or \'.\', and must start and end with an alphanumeric character (e.g. \'example.com\', regex used for validation is
                    \'[a-z0-9]([-a-z0-9]*[a-z0-9])?(\\\\.[a-z0-9]([-a-z0-9]*[a-z0-9])?)*\')","field":"metadata.name"}]},"code":422}\n'}
                    Traceback (most recent call last):
                      File "/home/taugspurger/src/kbatch-dev/kbatch/kbatch/kbatch/_core.py", line 224, in submit_job
                        r.raise_for_status()
                      File "/home/taugspurger/miniconda3/envs/ksubmit-server/lib/python3.9/site-packages/httpx/_models.py", line 1507, in raise_for_status
                        raise HTTPStatusError(message, request=request, response=self)
                    httpx.HTTPStatusError: Client error '422 Unprocessable Entity' for url 'http://localhost:8050/services/kbatch/jobs/'
                    For more information check: https://httpstatuses.com/422
Traceback (most recent call last):
  File "/home/taugspurger/miniconda3/envs/ksubmit-server/bin/kbatch", line 33, in <module>
    sys.exit(load_entry_point('kbatch', 'console_scripts', 'kbatch')())
  File "/home/taugspurger/miniconda3/envs/ksubmit-server/lib/python3.9/site-packages/click/core.py", line 829, in __call__
    return self.main(*args, **kwargs)
  File "/home/taugspurger/miniconda3/envs/ksubmit-server/lib/python3.9/site-packages/click/core.py", line 782, in main
    rv = self.invoke(ctx)
  File "/home/taugspurger/miniconda3/envs/ksubmit-server/lib/python3.9/site-packages/click/core.py", line 1259, in invoke
    return _process_result(sub_ctx.command.invoke(sub_ctx))
  File "/home/taugspurger/miniconda3/envs/ksubmit-server/lib/python3.9/site-packages/click/core.py", line 1259, in invoke
    return _process_result(sub_ctx.command.invoke(sub_ctx))
  File "/home/taugspurger/miniconda3/envs/ksubmit-server/lib/python3.9/site-packages/click/core.py", line 1066, in invoke
    return ctx.invoke(self.callback, **ctx.params)
  File "/home/taugspurger/miniconda3/envs/ksubmit-server/lib/python3.9/site-packages/click/core.py", line 610, in invoke
    return callback(*args, **kwargs)
  File "/home/taugspurger/src/kbatch-dev/kbatch/kbatch/kbatch/cli.py", line 157, in submit
    result = _core.submit_job(
  File "/home/taugspurger/src/kbatch-dev/kbatch/kbatch/kbatch/_core.py", line 224, in submit_job
    r.raise_for_status()
  File "/home/taugspurger/miniconda3/envs/ksubmit-server/lib/python3.9/site-packages/httpx/_models.py", line 1507, in raise_for_status
    raise HTTPStatusError(message, request=request, response=self)
httpx.HTTPStatusError: Client error '422 Unprocessable Entity' for url 'http://localhost:8050/services/kbatch/jobs/'
For more information check: https://httpstatuses.com/422

Closes #31.