remove unused themes

manage.sh

@@ -88,15 +88,7 @@ npm_packages() {
 
     echo '[!] install NPM packages'
     cd -- "$BASE_DIR"
-    npm install less@2.7 less-plugin-clean-css grunt-cli
-
-    echo '[!] install NPM packages for oscar theme'
-    cd -- "$BASE_DIR/searx/static/themes/oscar"
-    npm install
-
-    echo '[!] install NPM packages for simple theme'
-    cd -- "$BASE_DIR/searx/static/themes/simple"
-    npm install
+    npm install less@2.7 less-plugin-clean-css
 }
 
 docker_build() {