Tech ENABLE_GLBEGIN_GLEND_REMOVAL - Textures rendering

(cherry picked from commit prusa3d/PrusaSlicer@1a47211bfc)

resources/shaders/flat_texture.fs

@@ -0,0 +1,10 @@
+#version 110
+
+uniform sampler2D uniform_texture;
+
+varying vec2 tex_coord;
+
+void main()
+{
+    gl_FragColor = texture2D(uniform_texture, tex_coord);
+}

resources/shaders/flat_texture.vs

@@ -0,0 +1,9 @@
+#version 110
+
+varying vec2 tex_coord;
+
+void main()
+{
+    gl_Position = ftransform();
+	tex_coord = gl_MultiTexCoord0.xy;
+}