Add index mapping for DOS1 briefs
Add index mapping for DOS1 briefs

DOS1 and DOS2 briefs will be in the same index as they are both
compatible with the same mapping. So we point them both at the same
index.

The mapping for that index is generated from the DOS2 config in the
frameworks repo, hence the index name.

alphagov/digitalmarketplace-api,alphagov/digitalmarketplace-api,alphagov/digitalmarketplace-api