Revert "Add alternate legacy browser content"

bigbluebutton-html5/client/legacy.jsx

bigbluebutton-html5/client/main.html

...uebutton-html5/imports/ui/components/legacy/component.jsx

bigbluebutton-html5/imports/ui/components/legacy/styles.css

bigbluebutton-html5/package.json

bigbluebutton-html5/private/locales/en.json

bigbluebutton-html5/server/main.js