Support for ARCore

Is your feature request related to a problem? Please describe.
ARCore is an quite oldish (2017-released) already SDK for doing AR/VR related things like measuring via your camera.

Now StreetComplete is working on integrating it.

The problem is it depends on Google Play Services/a proprietary app as far as I see.

Describe the solution you'd like
Of course, it would be awesome if one could make it work:

• if one chooses to install the proprietary ARCore app
• or even without the ARCore and only microG installed

Describe alternatives you've considered
I know especially the second solution is very likely a huge and quite impossible task for this project (or are FLOSS AI models and tensorflow stuff already enough to implement such a thing?), so that's why I also looked into your wiki status page but could not find that feature listed there.

As such, the alternative would be to document the (intended) support status at least.

Additional context

• Even Google only supports selected devices: https://developers.google.com/ar/devices
• Android docs: https://developers.google.com/ar/develop/java/quickstart
• Wikipedia article: https://en.wikipedia.org/wiki/ARCore

No source file or test is named. Start by reviewing the ARCore SDK and Android quickstart links, the StreetComplete integration discussion, and microG's implementation-status page. Establish whether the requested ARCore support or only its intended status can be documented, and define completion around that documented decision.