glClipControl in WebotsJS

[BenjaminDeleze]

trafficstars

WebGL does not have access to glClipControl. This causes several differences between Webots desktop and WebotsJS among them:

• GTAO is "lighter" in WebotsJS
• The "near" is a bit different
  • The clipping can be a bit different when two geometries are really close (1e-5)

It would be good to implement a equivalent of glClipControl or find a workaround to have the same behaviour in both Webots deskopt and WebotsJS.