Add the hello-pt-resnet example

[yhwen]

Fixes # .

Description

Add an example to show how to wrap up the Python function into a Python class for creating an object instance to use in the job API. It uses the torchvision ResNet to replace the SImpleNetwork in the hello-pt example.

Types of changes

• Non-breaking change (fix or new feature that would not break existing functionality).
• Breaking change (fix or new feature that would cause existing functionality to change).
• New tests added to cover the changes.
• Quick tests passed locally by running ./runtest.sh.
• In-line docstrings updated.
• Documentation updated.