[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.
These migrations should be refactored into new migrations, because we're not going to be flushing and rebuilding our database after each production push anymore.