examples/shaders: Add an example for deferred shading (#3496)

* add example for deferred rendering/shading

* adapt convention

---------

Co-authored-by: 27justin <me@justin.cx>

examples/shaders/resources/shaders/glsl330/deferred_shading.vs

@@ -0,0 +1,11 @@
+#version 330 core
+
+layout (location = 0) in vec3 vertexPosition;
+layout (location = 1) in vec2 vertexTexCoord;
+
+out vec2 texCoord;
+
+void main() {
+    gl_Position = vec4(vertexPosition, 1.0);
+    texCoord = vertexTexCoord;
+}