Option to automatically add Event ID to Event Description

[smnc]

Is your feature request related to a problem? Please describe.
There is no good way to get the Event ID of an event while on Google Calendar.

Describe the solution you'd like
A per server setting to automatically add the event ID to the event description of events.

Describe alternatives you've considered
There's the stupid workaround: https://stackoverflow.com/questions/32755413/how-can-i-find-the-event-id-of-my-google-calendar-event
Or a user can add the event to the event description manually.

Additional context
I think the cleanest implementation would just be to have the bot append the event ID to whatever the user inputs as the event description.

[NovaFox161]

counter point: event ID will be displayed twice on the DisCal site and discal embeds unless we add filtering for this... Which can be done, but complicates a lot of the logic for handling event descriptions.

There is also this: #76
Obviously discal needs better input/output sanitization, but I'm not really sure how to do this well... or cleanly

Opinions? maybe a catch-all issue/milestone for sanitizing everything and what features we want in that? (for example, allowing links inside of event descriptions and automatically parsing them to HTML or markdown depending on if its on the discal site or discal embeds respectively)

[smnc]

Counter-Counter-Point: Some users (those with external calendars) largely manage events through Google Calendar instead of the bot or the website, and there just isn't a way to get the event ID from Google.

But yeah, it can all be combined in a catch-all.