[FEATURE] Provide Ability to specify a proxy when installing PythonPyPiLibrary

**Problem Statement**
When we are installing an internal python library on serverless clusters, we need to specify an http proxy, which is possible through pip but not possible today with using SDK. 

**Proposed Solution**
Add an option to specify a proxy when intilizing PythonPyPiLibrary

**Additional Context**
Add any other context, references or screenshots about the feature request here.