Add workers number on Gunicorn

Add optimum workers number on Gunicorn, based on cpu numbers (https://docs.gunicorn.org/en/stable/design.html)

start.sh

@@ -140,7 +140,7 @@ else
     congrats
 
     nginx -c $(pwd)/nginx/$conf
-    gunicorn webodm.wsgi --bind unix:/tmp/gunicorn.sock --timeout 300000 --max-requests 250 --preload
+    gunicorn webodm.wsgi --bind unix:/tmp/gunicorn.sock --timeout 300000 --max-requests 250 --workers $((2*$(grep -c '^processor' /proc/cpuinfo)+1)) --preload 
 fi
 
 # If this is executed, it means the previous command failed, don't display the congratulations message