Merge pull request #4040 from Klauswk/html5-2x-captions-messages

bigbluebutton-html5/imports/api/2.0/captions/index.js

...on-html5/imports/api/2.0/captions/server/eventHandlers.js

...mports/api/2.0/captions/server/handlers/captionHistory.js

...ts/api/2.0/captions/server/handlers/captionOwnerUpdate.js

...imports/api/2.0/captions/server/handlers/captionUpdate.js

bigbluebutton-html5/imports/api/2.0/captions/server/index.js

...uebutton-html5/imports/api/2.0/captions/server/methods.js

...5/imports/api/2.0/captions/server/modifiers/addCaption.js

...mports/api/2.0/captions/server/modifiers/clearCaptions.js

...utton-html5/imports/api/2.0/captions/server/publishers.js

bigbluebutton-html5/imports/startup/client/base.jsx

...on-html5/imports/ui/components/closed-captions/service.js

...luebutton-html5/imports/ui/components/settings/service.js

bigbluebutton-html5/server/main.js