User administration: edit user; set user as admin;

client/stylesheets/base.less

client/views/admin/users/adminUserEdit.coffee

client/views/admin/users/adminUserEdit.html

client/views/admin/users/adminUserInfo.coffee

client/views/admin/users/adminUserInfo.html

client/views/admin/users/adminUsers.html

i18n/en.i18n.json

packages/rocketchat-lib/package.js

packages/rocketchat-lib/server/methods/setAdminStatus.coffee

packages/rocketchat-lib/server/methods/updateUser.coffee