create code-colors class

packages/rocketchat-highlight/highlight.coffee

...tchat-integrations/client/views/integrationsIncoming.html

...tchat-integrations/client/views/integrationsOutgoing.html

packages/rocketchat-markdown/markdowncode.coffee

packages/rocketchat-theme/server/colors.less

...es/rocketchat-ui-flextab/flex-tab/tabs/messageSearch.html

packages/rocketchat-ui-message/message/messageBox.html