add Pipfile and Pipfile.lock for use with pipenv

[csai-scraping](https://github.com/calpoly-csai/csai-scraping) uses [pipenv](https://pipenv.readthedocs.io/en/latest/) and it is just [simply intuitive](https://www.youtube.com/watch?v=GBQAKldqgZs).

Let's set that up here too

It should make issues like #82 less common and easier to resolve/communicate too

**Changes needed**
- [x] Pipfile
- [x] Pipfile.lock
- [ ] udpates to the README

**Here are 2 nice cheat sheets**
* https://gist.github.com/bradtraversy/c70a93d6536ed63786c434707b898d55
* https://medium.com/@bettercallshao/pythons-development-environment-manager-a-practitioner-s-cheat-sheet-55e44e99ac2a

**Another guide**
* https://realpython.com/pipenv-guide/

**Pipfiles are toml files**
* so [learn toml in Y minutes](https://learnxinyminutes.com/docs/toml/)