App-repository: Add sentiment-analysis app

[scblack321]

For 2023 TACCster Tapis tutorial we have developed an app with a docker image that works with Tapis under docker or singularity.
Add this app as an example for this repo.
Python code and Dockerfile under docker-builds directory of TACCster Tapis tutorial repo:
https://github.com/tapis-project/tapis-ml-tutorial