[Feature Request] Specify PyPi Repo for Package Installation

We need the ability to specify (in pipeline configuration) which Pypi repository to pull packages from. Many times a customer will want to only install **local** packages (that they've tested/scanned) instead of public versions. A good example is scipy or numpy. Can we please add a flag to either specify an internal URL (that obviously the pipeline can access) or **PUBLIC**?

No files, tests, or entry points are named. Start by locating pipeline configuration and the package-installation path, then determine how an internal repository URL and PUBLIC selection should be represented and validated. Done means configuration can select either source and coverage verifies both behaviors.

Written by the indexing model from the issue text.