Returning number of users that participated in each meeting in getRecordings call

...vy/org/bigbluebutton/api/RecordingServiceHelperImp.groovy

...-web/src/java/org/bigbluebutton/api/domain/Recording.java

...ebutton-web/web-app/WEB-INF/freemarker/get-recordings.ftl

...-playback/core/lib/recordandplayback/generators/events.rb

...and-playback/presentation/scripts/process/presentation.rb