Further cleanup

* Removes (partly) the ArchivingOrchestrator
* Removes the cli_feeder module, and makes it the 'default', allowing you to pass URLs directly on the command line, without having to use the cumbersome --cli_feeder.urls. Just do auto-archiver https://my.url.com
* More unit tests
* Improved error handling

src/auto_archiver/modules/thumbnail_enricher/thumbnail_enricher.py

@@ -28,7 +28,7 @@ class ThumbnailEnricher(Enricher):
         logger.debug(f"generating thumbnails for {to_enrich.get_url()}")
         for m_id, m in enumerate(to_enrich.media[::]):
             if m.is_video():
-                folder = os.path.join(ArchivingContext.get_tmp_dir(), random_str(24))
+                folder = os.path.join(self.tmp_dir, random_str(24))
                 os.makedirs(folder, exist_ok=True)
                 logger.debug(f"generating thumbnails for {m.filename}")
                 duration = m.get("duration")