Proper Add Date retrieval from local files

Feature description:

Allow Symfonium to read the Encoding Time id3 tag (TDEN) and use it as the add date information.

I think this tag represents more faithfully the add date of a file (than the modification date), since it is practically when the file was encoded (created).

And I think we can keep using the modification date as a fallback mechanism in case the TDEN tag doesn’t exist.

Problem solved:

My library is properly tagged, and the files also have a proper Add Date (when they were created/downloaded/encoded/etc) and Change Date (when they were modified).

I understand that Android doesn’t provide the Add Date, and from what I can tell Symphonium is using the Modification Date as the add date of the track/album/artist which I suppose is the only available date in the file.

My problem is that my library ends up with wrong add dates, so whenever I’m using playlists sorted by add date I always get wrong results.

Brought benefits:

Allow local file users to specify a proper add date through a standard id3 tag.

Other application solutions:

 None that I know of. 

Additional description and context:

 Adding a couple of references to the TDEN tag:

ID3 tag version 2.4.0 - Native Frames — Mutagen Specs 1.0 documentation;

Screenshots / Mockup: