Add wifi qrcode script and instructions

scripts/.gitignore

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+*.png

scripts/wifi.sh

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+#!/bin/bash
+
+if [ $# -ne 2 ]; then
+    echo "Format:"
+    echo "./wifi.sh <SSID> <PASSWORD>"
+    echo "The result will be in wifi.png"
+fi
+
+qrencode -s 6 -o "./img/wifi.png" "WIFI:T:WPA;S:$1;P:$2;;"
+
+echo "Your wifi qrcode is wifi.png !"
+echo "Your wifi qrcode is now in the local img folder as wifi.png"