Docs: Perlmutter Early Science (BLAST-WarpX#2674)

* Docs: Perlmutter Early Science

Document how to perform large runs.

* Change comment style

Co-authored-by: Edoardo Zoni <59625522+EZoni@users.noreply.github.com>

Author: 2 people

Tools/BatchScripts/batch_perlmutter.sh

@@ -10,6 +10,8 @@
 #SBATCH -N 4
 #SBATCH -J WarpX
 #SBATCH -A <proj>
+# for m3906 LBNL/AMP users: for large runs, comment in
+##SBATCH -q early_science
 #SBATCH -C gpu
 #SBATCH -c 32
 #SBATCH --ntasks-per-node=4