rename media plugin to ytdlp with backwards-compatible aliases

- Rename archivebox/plugins/media/ → archivebox/plugins/ytdlp/
- Rename hook script on_Snapshot__63_media.bg.py → on_Snapshot__63_ytdlp.bg.py
- Update config.json: YTDLP_* as primary keys, MEDIA_* as x-aliases
- Update templates CSS classes: media-* → ytdlp-*
- Fix gallerydl bug: remove incorrect dependency on media plugin output
- Update all codebase references to use YTDLP_* and SAVE_YTDLP
- Add backwards compatibility test for MEDIA_ENABLED alias

archivebox/tests/test_migrations_08_to_09.py

@@ -458,7 +458,7 @@ class TestFilesystemMigration08to09(unittest.TestCase):
                     'SAVE_READABILITY': 'True',
                     'SAVE_MERCURY': 'True',
                     'SAVE_PDF': 'True',
-                    'SAVE_MEDIA': 'True',
+                    'SAVE_YTDLP': 'True',
                     'SAVE_ARCHIVEDOTORG': 'True',
                     'SAVE_HEADERS': 'True',
                     'SAVE_HTMLTOTEXT': 'True',

archivebox/tests/test_migrations_helpers.py

@@ -1002,7 +1002,7 @@ def run_archivebox(data_dir: Path, args: list, timeout: int = 60, env: dict = No
     base_env['SAVE_READABILITY'] = 'False'
     base_env['SAVE_MERCURY'] = 'False'
     base_env['SAVE_GIT'] = 'False'
-    base_env['SAVE_MEDIA'] = 'False'
+    base_env['SAVE_YTDLP'] = 'False'
     base_env['SAVE_HEADERS'] = 'False'
     base_env['SAVE_HTMLTOTEXT'] = 'False'