feat: add modern EME support for FairPlay (#3776)

Add support for HLS com.apple.streamingkeydelivery through MSE/EME implementation.

Close #3346

## Tests
Tested on:
- Mac 11.6 Safari 15.2
- iOS 15.2 Safari 15.2
- Mac 11.6 Chrome 96 (for potential regressions on Widevine keySystem)

| Mode | DRM API | TS | CMAF (mono-key and multi-keys)
|---|---|---|---|
| file | EME | ✅  | ✅  |
| file | Legacy-prefixed | ✅   | ✅   |
| media-source | EME | **mux-js**: `encrypted` never fired<br />**real MSE**: `encrypted` event received, but with incorrect `sinf` initData (*1)  | ✅  |
| media-source | Legacy-prefixed | **mux-js**: `webkitneedkey` never fired<br/>**real MSE**: TBD  | 🔴 fails to append media segment to SourceBuffer (init segment ok) `(video:4) – "failed fetch and append: code=3015"` |

## Support table 
| Mode | DRM API | TS | CMAF (mono-key and multi-keys)
|---|---|---|---|
| file | EME | ✅  | ✅  |
| file | Legacy-prefixed | ✅   | ✅   |
| media-source | EME | 🚫 `4040: HLS_MSE_ENCRYPTED_MP2T_NOT_SUPPORTED`  | ✅  |
| media-source | Legacy-prefixed | 🚫 `4041: HLS_MSE_ENCRYPTED_LEGACY_APPLE_MEDIA_KEYS_NOT_SUPPORTED`  |🚫 `4041: HLS_MSE_ENCRYPTED_LEGACY_APPLE_MEDIA_KEYS_NOT_SUPPORTED` |

⚠️ Use EME APIs with multi-keys CMAF makes the video stalling with the audio continuing alone after a short time (~3 minutes in the stream, could be shorter, could be longer). Didn't find an explanation to that yet. I've observed the same behaviour with hls.js code so I don't think this is a player issue.

docs/tutorials/drm-config.md

@@ -184,6 +184,11 @@ Microsoft Documentation: https://docs.microsoft.com/en-us/playready/overview/sec
 
 NB: Audio Hardware DRM is not supported (PlayReady limitation)
 
+##### FairPlay
+
+Based on [Apple's Documentation](https://developer.apple.com/streaming/fps/),
+you should provide an empty string as robustness
+
 ##### Other key-systems
 
 Values for other key systems are not known to us at this time.