website: do no rely on integration npm package for gaufre logos

while the idea is great at first, in fact it's a bit weird to publish a
new package version for something people don't actually use except the
docs website… and it makes it easier to publish website updates.
Duplicate a bit to ease up everything

website/package.json

@@ -11,10 +11,8 @@
     "start": "node ./server.mjs",
     "build-backgrounds": "node ./bin/build-services-backgrounds.mjs",
     "build": "astro check && npm run build-backgrounds && astro build",
-    "copy-logos": "cp -r ./node_modules/@gouvfr-lasuite/integration/dist/logos/* ./src/assets/logos",
     "preview": "astro preview",
-    "astro": "astro",
-    "postinstall": "npm run copy-logos"
+    "astro": "astro"
   },
   "dependencies": {
     "@astrojs/check": "^0.5.10",