Fixed: Use Nzb title as scene name when available

- Use Nzb title as scene name when available
- Only use file name as scene name when its highly likely that it's an actual scene name
- Don't store `DRONE` as default release group in the DB
- Clean up the db removing obviously wrong scene names


Needs separate updates for ReleaseGroup & SceneName, for example, plenty of WEBDL releases don't have a release name but are perfectly valid as scenename.