Support Postgress Adaptor "psycopg2" in python_pip workflow

[sanathkr]

Description:
Customers using Postgress with Lamnbda in Python run into the problem where this library does not load in AWS Lambda. This is a build time problem and not a runtime one. AWS Lambda does not include necessary libpq.so file required by Postgress in the runtime. So people have to compile & statically link this library.

See: https://github.com/jkehler/awslambda-psycopg2
More: https://stackoverflow.com/questions/44855531/no-module-named-psycopg2-psycopg-modulenotfounderror-in-aws-lambda

Steps to reproduce the issue:
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Observed result:

Expected result:

Additional environment details (Ex: Windows, Mac, Amazon Linux etc)