[web-client] simple theme: build & development env based on vite.

Vite is a build tool, it consists of two major parts [1]:

- A dev server that provides rich feature enhancements over native ES modules,
  for example extremely fast Hot Module Replacement (HMR).

- A build command that bundles your code with Rollup, pre-configured to output
  highly optimized static assets for production.

[1] https://vite.dev/guide/

Signed-off-by: Markus Heiser <markus.heiser@darmarit.de>

manage

@@ -35,6 +35,9 @@ source "$(dirname "${BASH_SOURCE[0]}")/utils/lib_go.sh"
 # shellcheck source=utils/lib_redis.sh
 source "$(dirname "${BASH_SOURCE[0]}")/utils/lib_redis.sh"
 
+# shellcheck source=utils/lib_sxng_vite.sh
+source "$(dirname "${BASH_SOURCE[0]}")/utils/lib_sxng_vite.sh"
+
 PATH="${REPO_ROOT}/node_modules/.bin:${PATH}"
 
 # config
@@ -102,6 +105,7 @@ EOF
     test.help
     themes.help
     static.help
+    vite.help
     cat <<EOF
 environment ...
   SEARXNG_REDIS_URL : ${SEARXNG_REDIS_URL}