Add presenter upload capabilities

bigbluebutton-html5/client/stylesheets/bbb-icons.css

...n-html5/imports/api/presentations/server/eventHandlers.js

...esentations/server/handlers/presentationConversionDone.js

...entations/server/handlers/presentationConversionUpdate.js

...rts/api/presentations/server/methods/sharePresentation.js

...rts/api/presentations/server/modifiers/addPresentation.js

...tton-html5/imports/ui/components/modal/base/component.jsx

...tml5/imports/ui/components/modal/fullscreen/component.jsx

...mponents/presentation/presentation-uploader/component.jsx

.../components/presentation/presentation-uploader/service.js

...components/presentation/presentation-uploader/styles.scss

bigbluebutton-html5/public/fonts/BbbIcons/bbb-icons.sfd

bigbluebutton-html5/public/fonts/BbbIcons/bbb-icons.svg

bigbluebutton-html5/public/fonts/BbbIcons/bbb-icons.ttf

bigbluebutton-html5/public/fonts/BbbIcons/bbb-icons.woff