Tech ENABLE_GL_SHADERS_ATTRIBUTES - Added shaders for glsl version 140

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

resources/shaders/140/mm_contour.fs

@@ -0,0 +1,13 @@
+#version 140
+
+const float EPSILON = 0.0001;
+
+uniform vec4 uniform_color;
+
+void main()
+{
+    gl_FragColor = uniform_color;
+    // Values inside depth buffer for fragments of the contour of a selected area are offset
+    // by small epsilon to solve z-fighting between painted triangles and contour lines.
+    gl_FragDepth = gl_FragCoord.z - EPSILON;
+}