Fetch repeated events more efficiently

[maxpatiiuk]

When fetching events, call with singleEvents: false (see https://developers.google.com/calendar/api/v3/reference/events/list)

This way, instead of sending each instance of a repeated event, Google Calendar will send the rules on how the event repeats

This will potentially reduce the response size by a lot when fetching over large periods (i.e, a year)

[maxpatiiuk]

Doing testing showed that singleEvents: false is actually returning a larger response then singleEvents: true because it also includes canceled events.
That, in addition to the added burden of having to infer the instances of the events based on the recurrence rule makes singleEvents: false totally not useful.

As a quick test, I fetched all events for my KU Homework calendar for the entire year of 2022, and there are only 590 entries with singleEvents: true - and the response was returned in 0.5 seconds. In comparison, singleEvents: false returned 609 entries and also took 0.5 seconds.

This shows that fetching for the entire year is practical even without singleEvents: false