Add Google Calendar Feed (Option) To Convo Frontend

As a user, if I want to add the entire Convo calendar to my calendar app, I should be able to do so. 

1. Reveal the appropriate link (Staging link: https://staging.convo.cafe/api/services/calendar/feed?communityDomain=staging) on the frontend. 
2. Provide a quick 'Add to Calendar' option.  