Add 3D editor gizmo icons for Decal, LightmapProbe and FogVolume
- Tweak CPUParticles3D editor gizmo icon to use the same outline color as other gizmo icons. Make the internal icon easier to see by using an orange color instead of gray. Co-authored-by: MewPurPur <mew.pur.pur@abv.bg>
Splits Node3DGizmos into dedicated files.