Merge pull request #12316 from ramonlsouza/rm-unused

...-html5/imports/api/cursor/server/handlers/cursorUpdate.js

...button-html5/imports/ui/components/checkbox/component.jsx

...ponents/external-video-player/custom-players/peertube.jsx

...luebutton-html5/imports/ui/components/media/component.jsx

.../ui/components/presentation/default-content/component.jsx