Merge pull request #1734 from RocketChat/livechat-departments

...ages/rocketchat-livechat/client/collections/AgentUsers.js

...ketchat-livechat/client/collections/LivechatDepartment.js

...t-livechat/client/collections/LivechatDepartmentAgents.js

...rocketchat-livechat/client/collections/LivechatTrigger.js

...ages/rocketchat-livechat/client/stylesheets/livechat.less

...hat-livechat/client/views/app/livechatDepartmentForm.html

...tchat-livechat/client/views/app/livechatDepartmentForm.js

...cketchat-livechat/client/views/app/livechatDepartments.js

...ges/rocketchat-livechat/client/views/app/livechatUsers.js

...ocketchat-livechat/client/views/sideNav/livechatFlex.html

.../rocketchat-livechat/client/views/sideNav/livechatFlex.js

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

packages/rocketchat-livechat/package.js

packages/rocketchat-livechat/server/lib/getNextAgent.js

...ages/rocketchat-livechat/server/methods/saveDepartment.js

...s/rocketchat-livechat/server/models/LivechatDepartment.js

...etchat-livechat/server/models/LivechatDepartmentAgents.js

...cketchat-livechat/server/publications/departmentAgents.js