[In Progress] Scraping, Reference Ranges and Units

This is a pull request in progress. This PR includes work for practice and provider scraping (fixes #87), reference ranges (fixes #53) and units(fixes #82). I was almost done with scraping, but I decided to put more effort to scrape all the information I can find online. 

For reference ranges and units, there is more work to do. I have designed what I will be doing for units. For reference ranges, I will work on the front end and connecting reference ranges to record update values.
`minimum_value` and `maximum_value` won't always be valid here, I don't think. The `n` argument in `Faker::Number.number(n)` represents the number of digits, but `99` is greater than `000`.