feat: move storage path setting to configuration file

- change default storage path to /srv/libretime
- remove music dirs table
- use /tmp for testing storage
- storage dir should always have a trailing slash

api/libretime_api/storage/tests/views/test_file.py

@@ -24,13 +24,8 @@ class TestFileViewSet(APITestCase):
         self.assertEqual(response.status_code, 404)
 
     def test_exists(self):
-        music_dir = baker.make(
-            "storage.MusicDir",
-            directory=str(fixture_path),
-        )
         file = baker.make(
             "storage.File",
-            directory=music_dir,
             mime="audio/mp3",
             filepath=AUDIO_FILENAME,
         )