Allow changing the calendar display name

[skwde]

Checklist

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• I have read the FAQ and my problem isn't listed.
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Original issue: SimpleMobileTools/Simple-Calendar#2287

Currently the calendar name cannot be changed for display.

It would be fairly helpful to change the display name of a calender.
Take for instance the outlook default name 'Calendar', which isn't giving that much info away.

So it would be nice to be able to set a custom name for the calendars.

Related: SimpleMobileTools/Simple-Calendar#1777