website: enable Japanese language

website/src/_data/languages.json

@@ -45,6 +45,12 @@
             "flag": "/img/flags/it.svg",
             "enabled": true
         },
+        {
+            "label": "ja",
+            "name": "日本語",
+            "flag": "/img/flags/jp.svg",
+            "enabled": true
+        },
         {
             "label": "nl",
             "name": "Nederlands",

website/src/img/flags/jp.svg

@@ -0,0 +1,11 @@
+<svg xmlns="http://www.w3.org/2000/svg" id="flag-icons-jp" viewBox="0 0 640 480">
+  <defs>
+    <clipPath id="jp-a">
+      <path fill-opacity=".7" d="M-88 32h640v480H-88z"/>
+    </clipPath>
+  </defs>
+  <g fill-rule="evenodd" stroke-width="1pt" clip-path="url(#jp-a)" transform="translate(88 -32)">
+    <path fill="#fff" d="M-128 32h720v480h-720z"/>
+    <circle cx="523.1" cy="344.1" r="194.9" fill="#bc002d" transform="translate(-168.4 8.6) scale(.76554)"/>
+  </g>
+</svg>