Allow for Internet Calendars

I think it would be nice to allow other types of internet calendars (such as public calendars/holiday calendars/.ics, etc.) to show up on the calendar (other than google or outlook). Another use case would be if you want someone else's calendar to show up for scheduling purposes. Right now it looks like only calendars that you create and are associated with your account in Outlook are able to be added vs. other people's calendars. In my case I'd like to show my personal outlook calendar on my Amplenote account I use for work, but I'd only like for the events to show up as 'busy' or 'not-busy' for privacy reasons.