add simple rule that utilizes a conda environment

[balhoff]

This will be for learning/demonstration purposes so that we can build on it for further parts of the workflow. The rule could be something that simply loads the datasets into the pytorch library and prints some statistics.

I think this doc will provide some starting points: https://snakemake.readthedocs.io/en/stable/snakefiles/deployment.html#integrated-package-management

[KSoumya]

Initiated a PR that adds a simple rule utilizing conda environment for pytorch.