More accurate attendance/statistics

[SamuelWei]

Is your feature request related to a problem? Please describe.
The usage and attendance data is currently generated via polling the BBB-Server every minute.
This post_events script might generate this analytical data more accurate as it uses all meeting events.

https://github.com/bigbluebutton/bigbluebutton/blob/develop/record-and-playback/core/scripts/post_events/post_events_analytics_callback.rb

Describe the solution you'd like
Set the url and meetingKeepEvents during create, add route to capture data, analyse, transform and store.