Tech ENABLE_GL_SHADERS_ATTRIBUTES - Added shaders for glsl version 140

(cherry picked from commit prusa3d/PrusaSlicer@76d1d4949b)

resources/shaders/140/thumbnail.fs

@@ -0,0 +1,16 @@
+#version 140
+
+uniform vec4 uniform_color;
+uniform float emission_factor;
+
+// x = tainted, y = specular;
+in vec2 intensity;
+//varying float drop;
+in vec4 world_pos;
+
+void main()
+{
+    if (world_pos.z < 0.0)
+        discard;
+    gl_FragColor = vec4(vec3(intensity.y) + uniform_color.rgb * (intensity.x + emission_factor), uniform_color.a);
+}