Add metadata API implementation.
Add file metadata loading task.
Add basic UI interaction for metadata.
Fix empty metadata handling.
Change file and its metadata association.

Should fix sorting issues.
Remove metadata loading for non-video files.
Change metadata layout to auto fit columns.
Remove unused resources.
Fix saving files state.
Change metadata loading to be dynamic.
Merge branch 'metadata-dynamic-loading' into metadata-support
Merge branch 'metadata-support' into tablet-optimizations