Use Hugo extended for Sass/CSS (#13113)

scripts/sass.sh

@@ -1,38 +0,0 @@
-#!/bin/bash
-
-if [[ $# -eq 0 ]] ; then
-    echo "You must specify a command from the following: build, develop"
-    exit 0
-fi
-
-__build() {
-    echo "Building Kubernetes website CSS from Sass sources..."
-
-    for filename in case-study-styles styles; do
-        echo $filename
-        sass \
-            --style=compressed \
-            sass/$filename.sass static/css/$filename.css
-    done
-
-    echo "Done building CSS!"
-}
-
-__develop() {
-    echo "Watching Sass sources for changes..."
-
-    sass \
-        --watch \
-        sass/styles.sass:static/css/styles.css \
-        sass/case-study-styles.sass:static/css/case-study-styles.css
-}
-
-case $1 in
-    build)
-        __build
-    ;;
-
-    develop)
-        __develop
-    ;;
-esac