Add debugging-oriented player view layout

[defagos]

As a Pillarbox developer I would like to be able to quickly have a look at what is being played.

Acceptance criteria

• A demo player layout is available displaying various debugging information (e.g. current tracks, bitrates, etc.).

Hints

• On Apple TV debugging options can be enabled from the Developer settings. They could inspire us. Maybe there is also something similar available for iOS nowadays, making this task irrelevant.
• 17.4 adds AVVideoPerformanceMetrics which might be useful.

Tasks

• [ ] Add debbugging-oriented demo player layout.
• [ ] Add to selectable demo layouts.
• [ ] Add button to download and display the playlist within the app directly.
• [ ] Content of the error log (might display non-critical bandwidth-related stream issues in real time, e.g.).