[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>

client/simple/src/js/searxng.head.js

@@ -0,0 +1 @@
+import "./head/00_init.js";

client/simple/src/js/searxng.js

@@ -0,0 +1,7 @@
+import "./main/00_toolkit.js";
+import "./main/infinite_scroll.js";
+import "./main/keyboard.js";
+import "./main/mapresult.js";
+import "./main/preferences.js";
+import "./main/results.js";
+import "./main/search.js";