Closes #21369: Add lazy loading and decoding options for ImageAttr (#21444)

Introduces `load_lazy` and `decoding` parameters to `ImageAttr` for
enhanced image handling. Lazy loading improves page performance, while
configurable decoding options provide greater flexibility. Updates the
template to conditionally include these attributes in rendered HTML.

Fixes #21369

netbox/templates/ui/attrs/image.html

@@ -1,3 +1,3 @@
 <a href="{{ value.url }}">
-  <img src="{{ value.url }}" alt="{{ value.name }}" class="img-fluid" />
+  <img src="{{ value.url }}" alt="{{ value.name }}" class="img-fluid" {% if load_lazy %}loading="lazy" {% endif %} {% if decoding %}decoding="{{ decoding }}" {% endif %}/>
 </a>