Generate Kubeflow PyTorchJob SDK

[jinchihe]

Discussed in kubeflow/trainer#167, and requried by @johnugeorge.

The PR is includes:

• Generated PyTorchJob Python SDK from the way: Go type -> openapi -> swagger file -> PyTorch SDK.
• Manually update the SDK name to kubeflow-pytorchjob and from kubeflow import pytorchjob.
• Manually added some Client APIs such as create, get, update, delete ...
• Release frist version kubeflow-pytorch SDK to Pypi: https://pypi.org/project/kubeflow-pytorchjob/
• Drafted some docs and updated Readme file.
• Created a sample for the SDK usage.
• Added some CI tests for the SDK.
• Work around some testing problem below.

Next:

• Need to add more APIs for the SDK.
• Need to update CI tests due to Failed to set kubeflow in CI test. #229

[coveralls]

Coverage decreased (-62.4%) to 22.97% when pulling 1a30426 on jinchihe:generate_sdk into 5522f91 on kubeflow:master.

[jinchihe]

Failed to set kubeflow in CI test.

level=error msg="validating registry URL: validating GitHub registry URL: \"https://github.com/kubeflow/kubeflow/tree/master/kubeflow/reg
istry.yaml\" actual 404; expected 200"

Seems this caused by kubeflow/kubeflow#4484, the ksonnet registry has been removed, we need to enhance this.

[jinchihe]

/assign @johnugeorge @gaocegege
/cc @animeshsingh @richardsliu @jlewi

The PR is ready for reviewing now, please see the PR description section for details. Thanks a lot!

[johnugeorge]

Looks great. Thanks @jinchihe for this contribution

[johnugeorge]

/lgtm
/approve

[k8s-ci-robot]

[APPROVALNOTIFIER] This PR is APPROVED

This pull-request has been approved by: johnugeorge

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