[Accessibility] Current media player does not enable multiple audio tracks and thus prevents the upload of audio description files for users with impaired sight #6461

Describe the bug

According to 301 559, Section 7.2.1: Where ICT displays video with synchronized audio, it shall provide a mechanism to select and play available audio description to the default audio channel.

To Reproduce

1. Upload a video to DSpace
2. Examine the audio player -- the option to upload and play description files in the audio track is not available

Expected behavior

Repo managers or sys admins should be able to upload an audio description file along with the video. Users should then be able to select between the original audio track and the track that contains the audio with descriptions. Alternatively, a player could also allow users to select and play multiple tracks, separating each track clearly for better controls.

Related work

Related to #6460. Both limitations would benefit from the implementation of a more accessibility-focused media player, such as the HTML5-based Able player.