New SimConnect variable: Reference datum position

Found the post from last year here:
https://devsupport.flightsimulator.com/t/3077 And the official comments:
[Live Dev Q&A; - April 27th, 2022 - Community / News and Announcements -
Microsoft Flight Simulator Forums](https://forums.flightsimulator.com/t/live-
dev-q-a-april-27th-2022/516747)

Chat question – Is there any plans to open the camera api for 3rd party devs
or improve it? A large part of the Community has been wanting a more
advanced camera system.

Jorg – We are going to make improvements. We want to have the best
system in the base sim. We still need to discuss about this.