feat: revamp footer layout and improve section separation

Redesigned the footer in `footer.html` to use a light background with dark text, adopting a more modern aesthetic and enhancing readability. The layout now utilizes a responsive grid, separating content into two columns for better organization on wider screens.

In `index.html`, added conditional rendering of horizontal rules between sections, omitting the rule after the last section. This change improves visual flow and reduces unnecessary visual clutter on the page.

These changes collectively enhance the user interface's look and feel, aligning with modern web design practices and improving overall user experience.

src/structables/templates/footer.html

@@ -1,11 +1,21 @@
-<footer class="text-center">
-  <hr />
-  <p>
-    <a href="https://git.private.coffee/PrivateCoffee/structables"
-      >Structables Code (AGPLv3)</a
-    >
-  </p>
-  <p>
-    <a href="/privacypolicy">View privacy policy.</a>
-  </p>
+<footer class="bg-light text-dark py-4">
+  <div class="container">
+    <div class="row">
+      <div class="col-md-6 text-center text-md-left">
+        <p class="mb-1">
+          <a
+            href="https://git.private.coffee/PrivateCoffee/structables"
+            class="text-dark"
+          >
+            Structables Code (AGPLv3)
+          </a>
+        </p>
+      </div>
+      <div class="col-md-6 text-center text-md-right">
+        <p class="mb-1">
+          <a href="/privacypolicy" class="text-dark">View privacy policy</a>
+        </p>
+      </div>
+    </div>
+  </div>
 </footer>

src/structables/templates/index.html

@@ -36,7 +36,9 @@
       </div>
       {% endfor %}
     </div>
+    {% if section != sections[-1] %}
     <hr />
+    {% endif %}
   </section>
   {% endfor %}
 </div>