Need to mount additional directories in container to handle pip oddities

@ljchang @jcheong0428

Depending on the install type, e.g. `pip install package`, `pip install git+githuburl`... pip seems to create temporary files in: `/var/tmp...`, `/tmp/...`, and `.pip/....`, this makes it tricky to install new python packages even with our "external conda environment hack" because of read-only issues.

This is there a global pip config, I'm missing or some way to predict its behavior more reliably?
See maybe this issue https://github.com/pypa/pip/issues/4262 ?