fix(downloaders): replace outdated baraag downloader

Downloaders/Baraag/README.md

@@ -0,0 +1,17 @@
+[See the help files for how to add downloaders to Hydrus](https://hydrusnetwork.github.io/hydrus/help/adding_new_downloaders.html)
+
+This downloader pulls images at their original size directly from Baraag. If
+you've muted a status (or "toot") through mastodon/Baraag's web UI, any images
+from that status will be excluded from the results returned to Hydrus.
+
+You might get away with running this without cookies / logging in but it's
+likely you'll get rate limited unless you import your session cookies to Hydrus.
+Even if you're properly authenticated, it's likely Baraag will still rate limit
+you after a while. Hydrus _should_ handle this smoothly and back off when rate
+limited.
+
+Future work:
+
+In theory, Hydrus's veto ability should support some simple form of client-side
+filtering, allowing us to exclude any statuses we've filtered out of our feeds,
+though I haven't explored this yet.