replace slippers with django-cotton

main reason: slippers cannot pass request via context inside its
components, making it annoying to use template takes that take request.
more reasons: not actively worked on, no named slots, having to define
components in components.yaml + new components do not get registered
without restarting server

games/templates/cotton/button_old.html

@@ -0,0 +1,13 @@
+{% comment %}
+title
+text
+{% endcomment %}
+<a href="{{ link }}"
+   title="{{ title }}"
+   class="truncate max-w-xs py-1 px-2 text-xs bg-green-600 hover:bg-green-700 focus:ring-green-500 focus:ring-offset-blue-200 text-white transition ease-in duration-200 text-center font-semibold shadow-md focus:outline-none focus:ring-2 focus:ring-offset-2 rounded-sm">
+    {% comment %} <svg xmlns="http://www.w3.org/2000/svg" fill="none" viewBox="0 0 24 24" stroke-width="1.5" stroke="currentColor" class="self-center w-6 h-6 inline">
+    <path stroke-linecap="round" stroke-linejoin="round" d="M5.25 5.653c0-.856.917-1.398 1.667-.986l11.54 6.348a1.125 1.125 0 010 1.971l-11.54 6.347a1.125 1.125 0 01-1.667-.985V5.653z" /> 
+    </svg>
+    {% endcomment %}
+    {{ text }}
+</a>