Remove MediaTrack dictionaries from BCD

[queengooborg]

This PR removes the MediaTrackConstraints, MediaTrackSettings, and MediaTrackSupportedConstraints dictionaries from BCD. These are a type (ex. a dictionary, enum, mixin, constant or WebIDL typedef) that we have explicitly stated not to document separately from the feature(s) that depend on it, as they are virtually invisible to the end developer.

Coverage Increase: removes 42 features, increasing collector coverage from 89.48% to 89.75%

[hamishwillee]

@queengooborg @Elchi3 SO does this mean that you have merged the compatibility data into the places where this data is used? Such as if you remove MediaTrackSupportedConstraints then the data would have to be captured as an update to BCD for MediaDevices.getSupportedConstraints() indicating the different versions in which the properties in the return value were added. Similar for the other cases. Otherwise we're throwing away useful compat data that would be hard to test for. Ditto for the other dictionaries.

[queengooborg]

Content changes have now been merged!