added script for packaging

package.sh

@@ -0,0 +1,11 @@
+#!/bin/bash
+
+if [ ! -f manifest.json ]; then
+  echo "Please execute inside project directory!"
+fi
+
+excludedfiles=("package.sh" "icons/pwdhash-icon.svg")
+
+currentversion=$(grep -oP '"version": "\K[\d.]+' manifest.json)
+
+zip -r -FS ../pwdhash-${currentversion}.zip * -x ${excludedfiles[@]}