Add [SdfLib](https://github.com/UPC-ViRVIG/SdfLib) plugin to first-party SDFs.

The following dependencies are disabled with a cmake patch file.
- Enoki
- OpenMP
- Assimp
- FCPW

PiperOrigin-RevId: 565352386
Change-Id: Icff9de68408e0afa2032bb83b24491fc4e41d181

src/engine/engine_ray.c

@@ -774,6 +774,9 @@ mjtNum ray_sdf(const mjModel* m, const mjData* d, int g,
     if (distance < 1e-8) {
       return distance_total;
     }
+    if (distance > 1e6) {
+      break;
+    }
   }
 
   // reset counter