[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>

searxng_extra/update/update_pygments.py

@@ -13,7 +13,7 @@ from pygments.formatters.html import HtmlFormatter
 
 from searx import searx_dir
 
-LESS_FILE = Path(searx_dir) / 'static/themes/simple/src/generated/pygments.less'
+LESS_FILE = Path(searx_dir).parent / 'client/simple/generated/pygments.less'
 
 HEADER = f"""\
 /*