Merge pull request #12422 from germanocaumo/poll-chat-refactor

...ports/api/group-chat-msg/server/modifiers/addSystemMsg.js

...tml5/imports/api/polls/server/handlers/sendPollChatMsg.js

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

...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

...-chat-item/message-chat-item/poll-list-item/component.jsx

...ow-chat-item/message-chat-item/poll-list-item/styles.scss

...-html5/imports/ui/components/poll/live-result/styles.scss

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

...luebutton-html5/imports/ui/components/polling/styles.scss