* Added rtcstats

* increased webpack performance size warning to 830K

* Addressed most of Saghuls and Andrei's review comments.

* moved rtcstatsUseLibJitsi from analytics to testing

* refactor ljm rtcstats, use ljm conference events

* remove debug logs

* remove wrongly named files

* rename rtcstats module

* fix test

* address code review

* fix pack error

* address code review

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Co-authored-by: Nils Ohlmeier <github@ohlmeier.org>

Add a performance stat around long tasks. Chrome supports PerformanceObserver API that lets us
register for long tasks event. Any task that takes longer than 50ms is considered a long task.