add palabos benchmark example

p/palabos/README

+How to compile Palabos cavity3d benchmakr example
+
+    wget http://www.palabos.org/images/palabos_releases/palabos-v2.0r0.tgz
+    tar xf palabos-v2.0r0.tgz
+    pushd palabos-v2.0r0/examples/benchmarks/cavity3d
+    module load foss/2018b
+    make
+    popd
+
+Launch cavity3d
+
+sbatch runPalabosCavity3d.sh 

p/palabos/runPalabosCavity3d.sh

+#!/bin/sh
+#SBATCH --job-name=test-palabos
+#SBATCH --cpus-per-task=1
+#SBATCH --tasks=16
+#SBATCH --partition=debug
+#SBATCH --time=15:00
+#SBATCH --reservation=capello_96
+
+module load foss/2018b
+
+# resolution http://wiki.palabos.org/plb_wiki:benchmarks
+N=400
+
+srun palabos-v2.0r0/examples/benchmarks/cavity3d/cavity3d $N