Backstop paths/filenames break Windows build

[HaSistrunk]

Describe the bug

Because of illegal characters in filepaths from Backstop, Windows machines can't checkout branches containing these paths.

Expected behavior

yarn serve should build the site locally with no errors

Error message or screenshots

error: invalid path 'backstop_data/request_reference/search_facets__api.rockarch.org_facets?category=&limit=40&query=banana__get'

Impact on your work

For collaborators using Windows, this blocks local development/testing.

Additional context

Two possibilities:

1. See if we can address this in the Backstop configuration (potentially by escaping characters in these paths)
2. Add a new Dockerfile or build stage in the existing Dockerfile which would allow the local container to be used for development.