Raycaster: Only check for intersections when pointer moves or on click events

[Tinoooo]

Is your feature request related to a problem? Please describe.
In the current implementation, the check for intersecting objects happens on every single render cycle (see here).

Describe the solution you'd like
We could change the code in a way that the intersections are only calculated when the pointer moves or when the canvas is being clicked. Maybe there is even a possibility to only check meshes in which the respective directives (@click, ...) are used. These changes would lead to performance improvements.

Suggested solution
See above.