Implements chat using react context as middleware

bigbluebutton-html5/client/main.jsx

...tml5/imports/ui/components/chat/chat-logger/ChatLogger.js

bigbluebutton-html5/imports/ui/components/chat/component.jsx

bigbluebutton-html5/imports/ui/components/chat/container.jsx

...ml5/imports/ui/components/chat/message-form/container.jsx

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

...imports/ui/components/chat/time-window-list/component.jsx

...imports/ui/components/chat/time-window-list/container.jsx

...5/imports/ui/components/chat/time-window-list/styles.scss

...chat/time-window-list/time-window-chat-item/component.jsx

...chat/time-window-list/time-window-chat-item/container.jsx

...ist/time-window-chat-item/message-chat-item/component.jsx

...s/chat/time-window-list/time-window-chat-item/styles.scss

...ts/ui/components/components-data/chat-context/adapter.jsx

...ts/ui/components/components-data/chat-context/context.jsx

...s/ui/components/components-data/users-context/adapter.jsx

...s/ui/components/components-data/users-context/context.jsx

...ml5/imports/ui/components/context-providers/component.jsx

...on-html5/imports/ui/components/debug-window/component.jsx

...n-html5/imports/ui/components/subscriptions/component.jsx