Ajout icônes navbar avec effets hover et recherche locale

- Replace GitHub/Forgejo text links with SVG icons
- Add luminous hover effects on navbar icons
- Add local search plugin with FR/EN support

static/img/forgejo-logo.svg

@@ -0,0 +1,36 @@
+<svg viewBox="0 0 212 212" xmlns="http://www.w3.org/2000/svg">
+  <metadata xmlns:rdf="http://www.w3.org/1999/02/22-rdf-syntax-ns#" xmlns:cc="http://creativecommons.org/ns#" xmlns:dc="http://purl.org/dc/elements/1.1/">
+    <rdf:RDF>
+      <cc:Work rdf:about="https://codeberg.org/forgejo/meta/src/branch/readme/branding#logo">
+        <dc:title>Forgejo logo</dc:title>
+        <cc:creator rdf:resource="https://caesarschinas.com/"><cc:attributionName>Caesar Schinas</cc:attributionName></cc:creator>
+        <cc:license rdf:resource="http://creativecommons.org/licenses/by-sa/4.0/"/>
+      </cc:Work>
+    </rdf:RDF>
+  </metadata>
+  <style type="text/css">
+    circle {
+      fill: none;
+      stroke: #000;
+      stroke-width: 15;
+    }
+    path {
+      fill: none;
+      stroke: #000;
+      stroke-width: 25;
+    }
+    .orange {
+      stroke:#ff6600;
+    }
+    .red {
+      stroke:#d40000;
+    }
+  </style>
+  <g transform="translate(6,6)">
+    <path d="M58 168 v-98 a50 50 0 0 1 50-50 h20" class="orange"/>
+    <path d="M58 168 v-30 a50 50 0 0 1 50-50 h20" class="red"/>
+    <circle cx="142" cy="20" r="18" class="orange"/>
+    <circle cx="142" cy="88" r="18" class="red"/>
+    <circle cx="58" cy="180" r="18" class="red"/>
+  </g>
+</svg>

static/img/github-mark.svg

@@ -0,0 +1 @@
+<svg width="98" height="96" xmlns="http://www.w3.org/2000/svg"><path fill-rule="evenodd" clip-rule="evenodd" d="M48.854 0C21.839 0 0 22 0 49.217c0 21.756 13.993 40.172 33.405 46.69 2.427.49 3.316-1.059 3.316-2.362 0-1.141-.08-5.052-.08-9.127-13.59 2.934-16.42-5.867-16.42-5.867-2.184-5.704-5.42-7.17-5.42-7.17-4.448-3.015.324-3.015.324-3.015 4.934.326 7.523 5.052 7.523 5.052 4.367 7.496 11.404 5.378 14.235 4.074.404-3.178 1.699-5.378 3.074-6.6-10.839-1.141-22.243-5.378-22.243-24.283 0-5.378 1.94-9.778 5.014-13.2-.485-1.222-2.184-6.275.486-13.038 0 0 4.125-1.304 13.426 5.052a46.97 46.97 0 0 1 12.214-1.63c4.125 0 8.33.571 12.213 1.63 9.302-6.356 13.427-5.052 13.427-5.052 2.67 6.763.97 11.816.485 13.038 3.155 3.422 5.015 7.822 5.015 13.2 0 18.905-11.404 23.06-22.324 24.283 1.78 1.548 3.316 4.481 3.316 9.126 0 6.6-.08 11.897-.08 13.526 0 1.304.89 2.853 3.316 2.364 19.412-6.52 33.405-24.935 33.405-46.691C97.707 22 75.788 0 48.854 0z" fill="#24292f"/></svg>