Feature: Enable quote preservation to DbtYAML class by default

[nicholasyager]

Description of Changes

Update DbtYAML class to have quote preservation on by default. This is accomplished by setting preserve_quotes = True during initialization of the class.

Resolves: #66

Example Output

 - name: customer_type
    description: Options are 'new' or 'returning', indicating if a customer has ordered more than once or has only placed their first order to date.
    tests:
      - accepted_values:
          values: ["new", "returning"]