[web-client] simple theme: refactor jinja_svg_catalog and cleanup icon names

This patch implements the template generation of the template:

  searx/templates/simple/icons.html

by the way the icon set (the icon names) has been normalized:

  film-outline   --> film
  magnet-outline --> magnet
  ..
  warning        --> alert

Some missing (categorie) icons had been added.

Some of the ionicons are not suitable for a dark theme, we fixed the svg
manually in src/svg/ionicons:

- https://github.com/searxng/searxng/pull/4284#issuecomment-2680550342

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

client/simple/package.json

@@ -4,15 +4,18 @@
   "type": "module",
   "scripts": {
     "build": "vite build",
-    "fix": "eslint --fix && stylelint --fix strict 'src/**/*.{css,scss,sass,less,styl,vue,svelte}'"
+    "fix": "eslint --fix && stylelint --fix strict 'src/**/*.{css,scss,sass,less,styl,vue,svelte}'",
+    "icons.html": "node theme_icons.js"
   },
   "devDependencies": {
     "@eslint/js": "^9.19.0",
     "copy-webpack-plugin": "^12.0.2",
     "css-loader": "^7.1.2",
+    "edge.js": "^6.2.1",
     "eslint": "^9.19.0",
     "filemanager-webpack-plugin": "^8.0.0",
     "globals": "^15.14.0",
+    "ionicons": "^7.4.0",
     "leaflet": "^1.9.4",
     "less": "^4.2.2",
     "less-loader": "^12.2.0",