[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.
It's nicer if these values are more general:
```
@value = Faker::Number.number(2)
```
And then in the `it` block...
```
build(..., minimum_value: @value, maximum_value: @value - Faker::Number.number(2))...
```
or similarly...
```
build(..., minimum_value: @value, maximum_value: @value)...
```