Debug Helper: Add Theme Review Import

#### Is your feature request related to a problem? Please describe.
The Debug Helper could be a way to quickly import test data to a site.

#### Describe the solution you'd like
Add an easy way to import the TRT test data. It's a comprehensive import that the theme review team uses, so it should be pretty decent at giving us some things to look at.

#### Describe alternatives you've considered
Writing our own. We could still do that and just swap out the file when it's done.

#### Additional context

The issue names the Debug Helper and TRT test data but no file, test, or entry point. Start by locating the Debug Helper and the theme-review test-data source; done means providing an easy import path for that data and verifying it works on a site.

Written by the indexing model from the issue text.