Sculpt/Paint: Add Paint Studio Light preset

This studio light preset is designed for color painting tasks. As color
are multiplied on top of the current studio light/matcap, this should be
as white as possible and with very soft speculars to avoid color
distorsion while showing the volume of the mesh.

Reviewed By: jbakker, JulienKaspar

Differential Revision: https://developer.blender.org/D8209

release/datafiles/studiolights/studio/paint.sl

@@ -0,0 +1,48 @@
+version 1
+light_ambient.x 0.000000
+light_ambient.y 0.000000
+light_ambient.z 0.000000
+light[0].flag 1
+light[0].smooth 0.374078
+light[0].col.x 1.000000
+light[0].col.y 1.000000
+light[0].col.z 1.000000
+light[0].spec.x 0.281010
+light[0].spec.y 0.281010
+light[0].spec.z 0.281010
+light[0].vec.x 0.033898
+light[0].vec.y 0.406780
+light[0].vec.z 0.912897
+light[1].flag 1
+light[1].smooth 0.135593
+light[1].col.x 0.342384
+light[1].col.y 0.342384
+light[1].col.z 0.342384
+light[1].spec.x 0.000000
+light[1].spec.y 0.000000
+light[1].spec.z 0.000000
+light[1].vec.x 0.000000
+light[1].vec.y 0.372881
+light[1].vec.z 0.927879
+light[2].flag 1
+light[2].smooth 0.630803
+light[2].col.x 0.201899
+light[2].col.y 0.156801
+light[2].col.z 0.147954
+light[2].spec.x 0.066807
+light[2].spec.y 0.058182
+light[2].spec.z 0.063403
+light[2].vec.x 0.079643
+light[2].vec.y -0.681392
+light[2].vec.z -0.727573
+light[3].flag 1
+light[3].smooth 0.200000
+light[3].col.x 0.220250
+light[3].col.y 0.037944
+light[3].col.z 0.047254
+light[3].spec.x 0.106531
+light[3].spec.y 0.080187
+light[3].spec.z 0.063969
+light[3].vec.x -0.081162
+light[3].vec.y -0.173044
+light[3].vec.z -0.981564