[Calendar] Allow Calendar iCal feed and ISC files the option to include more than the past 30 days

[RebeccaMeyer]

Problem statement:

The Calendar iCal feed and ISC export only include calendar events from the past 30 days (https://community.canvaslms.com/t5/Student-Guide/How-do-I-view-the-Calendar-iCal-feed-to-subscribe-t...). This makes it difficult for instructors to get an overview of their entire course in their personal preferred calendar app, where it can be seen in context with the rest of their personal calendar. Being able to see all of the past course calendar events in a personal calendar app is useful for instructors for time management for a current course and for planning their future courses.

Proposed solution:

Allow an option for a calendar feed and ISC export that includes more than the past 30 days. Specifying the entirety of the course would be useful.

User role(s):

instructor,student