add lock setting option to hide viewers from each other

...re/apps/users/ChangeLockSettingsInMeetingCmdMsgHdlr.scala

...luebutton/core/apps/users/GetLockSettingsReqMsgHdlr.scala

...n/scala/org/bigbluebutton/core/running/MeetingActor.scala

.../main/scala/org/bigbluebutton/core2/MeetingStatus2x.scala

...in/scala/org/bigbluebutton/common2/domain/Meeting2x.scala

.../main/scala/org/bigbluebutton/common2/msgs/UsersMgs.scala

...on-web/src/main/java/org/bigbluebutton/api/ApiParams.java

.../main/java/org/bigbluebutton/api/ParamsProcessorUtil.java

...java/org/bigbluebutton/api/domain/LockSettingsParams.java

...rc/main/scala/org/bigbluebutton/api2/BbbWebApiGWApp.scala

...imports/api/meetings/server/methods/toggleLockSettings.js

...html5/imports/api/meetings/server/modifiers/addMeeting.js

...ports/api/meetings/server/modifiers/changeLockSettings.js

...on-html5/imports/ui/components/lock-viewers/component.jsx

...5/imports/ui/components/lock-viewers/notify/component.jsx

...uebutton-html5/imports/ui/components/user-list/service.js

...ton-html5/imports/ui/components/video-provider/service.js

bigbluebutton-html5/private/locales/en.json

bigbluebutton-web/grails-app/conf/bigbluebutton.properties

bigbluebutton-web/grails-app/conf/spring/resources.xml