create transparent color classes

packages/rocketchat-emoji-custom/admin/adminEmoji.html

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

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

packages/rocketchat-livechat/app/client/views/message.html

packages/rocketchat-markdown/markdown.coffee

...t-message-snippet/client/tabBar/views/snippetMessage.html

packages/rocketchat-oembed/client/oembedAudioWidget.html

packages/rocketchat-oembed/client/oembedFrameWidget.html

packages/rocketchat-oembed/client/oembedSandstormGrain.html

packages/rocketchat-oembed/client/oembedUrlWidget.html

packages/rocketchat-oembed/client/oembedVideoWidget.html

packages/rocketchat-oembed/client/oembedYoutubeWidget.html

...es/rocketchat-spotify/lib/client/oembedSpotifyWidget.html

packages/rocketchat-theme/client/imports/base.less

packages/rocketchat-theme/server/colors.less

packages/rocketchat-ui-admin/admin/admin.html

packages/rocketchat-ui-admin/admin/adminInfo.html

packages/rocketchat-ui-admin/admin/rooms/adminRooms.html

packages/rocketchat-ui-admin/admin/users/adminUsers.html

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