macosx: Add ability for navigation state and stack to keep track of currently-viewed media source
This MR makes the library navigation stack keep track of media library actions such as browsing through the file system, allowing the user to use the nav buttons to go backwards/forwards in the file system
Screen_Recording_2022-11-14_at_19.18.14
Signed-off-by: Claudio Cambra developer@claudiocambra.com