Use page-loading animation when waiting subs

...s/rocketchat-mailer/client/views/mailerUnsubscribe.coffee

packages/rocketchat-ui-login/login/layout.js

packages/rocketchat-ui-master/master/main.coffee

packages/rocketchat-ui-master/master/main.html

packages/rocketchat-ui-master/master/pageLoading.html

packages/rocketchat-ui-master/package.js

packages/rocketchat-ui-master/server/inject.js

packages/rocketchat-ui/views/app/secretURL.coffee

packages/rocketchat-ui/views/cmsPage.coffee

packages/rocketchat-ui/views/fxos.coffee