refactor(Track): Rename extra to data, enforce type as dict

Setting data as a dictionary allows more places of code (including DASH, HLS, Services, etc) to get/set what they want by key instead of typically by index (list/tuple). Tuples or lists were typically in services because DASH and HLS stored needed data as a tuple and services did not want to interrupt or remove that data, even though it would be fine.

devine/core/manifests/dash.py

@@ -207,7 +207,12 @@ class DASH:
                         language=track_lang,
                         is_original_lang=language and is_close_match(track_lang, [language]),
                         descriptor=Video.Descriptor.DASH,
-                        extra=(rep, adaptation_set),
+                        data={
+                            "dash": {
+                                "representation": rep,
+                                "adaptation_set": adaptation_set
+                            }
+                        },
                         **track_args
                     ))