Make volumetric light effect strength server controllable

- Make volumetric light effect strength server controllable
- Separate volumetric and bloom shader pipeline
- Require bloom to be enable, scale godrays with bloom

client/shaders/volumetric_light/opengl_vertex.glsl

@@ -0,0 +1,12 @@
+#ifdef GL_ES
+varying mediump vec2 varTexCoord;
+#else
+centroid varying vec2 varTexCoord;
+#endif
+
+
+void main(void)
+{
+	varTexCoord.st = inTexCoord0.st;
+	gl_Position = inVertexPosition;
+}