open up content blob download for textual(-ish) files
It's time to open up raw content blob download, from URLs like this.
For now, we'd like to allow download only of files that have been detected as being textual-ish, by swh-indexer. (And yes, this means contents that haven't been processed yet by swh-indexer will not be available for download.)
Migrated from T694 (view on Phabricator)