Add a script to easily update the default Bootstrap theme

Author: TheElectronWill

doc-tool/bootstrap-theme/build.sh

@@ -0,0 +1,6 @@
+#!/bin/sh
+cd "$(dirname "$0")"
+npm run build
+echo "Copying css file..."
+cp target/bootstrap.min.css ../resources/css/bootstrap.min.css
+echo "Bootstrap css updated."