Solution in-world so new users know what controls they have

[DougReeder]

Is your feature request related to a problem? Please describe.
Many, if not most, rooms need to make new users feel welcome. (See https://web.archive.org/web/20240520035510/https://hubs.mozilla.com/labs/setting-the-scene-immersive-space-design/ for why)
One issue is most users are new to Hubs, and don't know the controls
The examples in the blog post have posters or videos in-world to help users learn the controls. However, these controls are different for different platforms, and we currently have no good way to make content responsive to user platform.

Also, the easier it is for world creators to include this, the more worlds will have it, and the more users will have positive first experiences with Hubs.

Describe the solution you'd like
Ideally, we'd have a general solution for elements that are responsive to the user platform. We would provide standard text & diagrams for world builders to put in.

Describe alternatives you've considered
We have a UI element on personal computers that provides a few tips, but this is not available on other platforms and provide very little content.

We could generate graphics with the controls for each platform. These could be placed in Image elements. However users that first see content irrelevant to them in one image element are less likely to look at the others. Also, a "wall of text" is not a welcoming experience.

We could generate videos with the controls for each platform. These could be placed in Video elements. Either they auto-play, so the users is overloaded with moving images, most of which are irrelevant, or the user has to click on a video to start it — before they've learned any of the controls!

A single-purpose element that just gave directions would work, but would provide less value.

As a hack, I include a link to https://github.com/Hubs-Foundation/hubs/wiki/Hubs-Controls in my worlds near the spawn point, but that takes users out of the world.

Additional context
Virtual Ability Island in Second Life

NYU VR Orientation Space