[FR] Dynamic hint/tooltip for interaction

[KronosTheLate]

The plotly backend from Plots.jl does something amazing - showing tooltips for the first time you interact with a new plot:
Video of plotly behaviour

This is simply fantastic for new users, and the transparency and quick fade of the tooltip makes it not-that-annoying for users who know the tip. Could something similar be added for Makie's interactive plots?
This would greatly alleviate the problems discussed at #827.

[SimonDanisch]

I don't really have time to work on this, but I think, at least in GLMakie/WGLMakie we could have a few UI elements + some tooltips as a default much like Plotly.
Anyone should be able to prototype something like that, so PRs are welcome!
If it's not clear where to integrate such a UI, I'm happy to help with that part.