fix permission overlay positioning, localizes messages

bigbluebutton-html5/imports/api/audio/client/bridge/sip.js

...rts/ui/components/audio/permissions-overlay/component.jsx

bigbluebutton-html5/imports/ui/components/audio/service.js

...uebutton-html5/imports/ui/services/audio-manager/index.js

bigbluebutton-html5/private/locales/en.json