Applies an rule-of-thirds grid overlay to the self-preview video window. This is useful for passively nudging guests to better center themselves while on camera.
As of v19.0, this only works for guests of a room or of a faux-room. It doesn't yet support basic push/view links, as those don't use the auto-mixer code, which is where this code is currently applied.
default version of &grid
Changes in Version 22 (currently alpha)
Added the option to customize the &grid effect by passing an image link (can help center guests).
A transparent PNG or an SVG file are the recommended options.
It will stretch to cover the camera preview-area, so probably best to keep things 16:9 aspect if needed.
URL can be URL-encoded, for more complex URLs. Simple URLs might work without.
Technically this can be used as an overlay for other things, but it only works with the self-preview.
