Add filter to current livechats screen

.eslintrc

packages/rocketchat-i18n/i18n/en.i18n.json

packages/rocketchat-i18n/i18n/pt.i18n.json

...tchat-livechat/client/views/app/livechatCurrentChats.html

...ketchat-livechat/client/views/app/livechatCurrentChats.js

packages/rocketchat-livechat/server/models/Rooms.js

.../rocketchat-livechat/server/publications/livechatRooms.js

packages/rocketchat-theme/assets/stylesheets/base.less