WIP: fall back to local file indexer if baloo indexing is not available for all folders
In case baloo is active, but some folders are excluded (especially for external disks), Elisa did not have a chance to detect the files, since the local file indexers is disabled. Solve this by actually checking the file path whether it is indexed by baloo and keep the local file indexer active for the remaining folders.
Test plan: Create a folder with some music and exclude it from baloo indexing. With this patch, the music is correctly scanned and added to the playlist. Symlinks should also still work.