Missing basic information from the MP4 metadata

[cedricopfermann]

Some of the basic file metadata from the Windows Properties window are missing in the MP4 parser. This pull request add some of these information like : Title, Subtitle, Rating, Keywords, Comments.

The current code allows whoever wants to add more information like Producers, Editors, Copyrights, etc.

Here is the documentation I used to code this pull request : https://mp4workshop.com/about