Lift max count limitations for point & line renderer

[Wumpf]

Currently, there is a hard maximum number of points and line segments we support for a single DrawData package in the renderer. It's not upon the viewer to do cutting this down either!

We should be more clever on how we distribute data to the "data textures" we use to feed data into the respective vertex shaders.
It is conceivable that we'd have this limit only on WebGL where we can't use raw buffers! But this would require us to have two different shader & bindings for WebGL vs rest.

[Wumpf]

accidentally duplicated this ticket, but this is actually a better writeup: #3076