feat: Add config to support Pickle serializer customization

[markhsu-ms]

Change Summary

• Make Pickle serializer customizable so that user can overwrite dumps and loads behavior to support different data formate. It will be very useful when dealing with Py2 Py3 compatibility issue.

Highlight of Code Change

• Add DefaultSerializer with default pickling behavior
• Read TRANSMISSION_SERIALIZER from Django config setting, and then use the user provided serializer if class exists.

Code Sample

Create custom serializer class. Serializer must contains dumps and loads methods

# project/lib/django/serializer.py

import pickle

class CustomSerializer(object):
    def dumps(self, value):
        return pickle.dumps(value, 2)

    def loads(self, value):
        return pickle.loads(value, fix_imports=True, encoding="latin1")

Set TRANSMISSION_SERIALIZER with serializer path

# project/config/common/settings.py

TRANSMISSION_SERIALIZER = "lib.django.serializer.CustomSerializer"

[shortcut-integration]

This pull request has been linked to Clubhouse Story #63930: Python 3 transmissions library update.

[manav]

Looks good. we should also create a new tag.