refactor(virtualization): Port to declarative layout

Add declarative layout panels for Cluster, Cluster Group, Cluster Type,
Virtual Disk, and VM Interface, including addressing, VLAN assignment,
and FHRP group handling.

Expand the declarative layout primitives:
- add GFK attribute rendering support
- add panel for rendering context-provided tables
- update templates to support new panels/attrs

Closes #20923

netbox/templates/virtualization/panels/cluster_resources.html

@@ -0,0 +1,34 @@
+{% load helpers %}
+{% load i18n %}
+
+<div class="card">
+  <h2 class="card-header">{% trans "Allocated Resources" %}</h2>
+  <table class="table table-hover attr-table">
+    <tr>
+      <th scope="row"><i class="mdi mdi-gauge"></i> {% trans "Virtual CPUs" %}</th>
+      <td>{{ vcpus_sum|placeholder }}</td>
+    </tr>
+    <tr>
+      <th scope="row"><i class="mdi mdi-chip"></i> {% trans "Memory" %}</th>
+      <td>
+        {% if memory_sum %}
+          <span title={{ memory_sum }}>{{ memory_sum|humanize_ram_megabytes }}</span>
+        {% else %}
+          {{ ''|placeholder }}
+        {% endif %}
+      </td>
+    </tr>
+    <tr>
+      <th scope="row">
+        <i class="mdi mdi-harddisk"></i> {% trans "Disk Space" %}
+      </th>
+      <td>
+        {% if disk_sum %}
+          {{ disk_sum|humanize_disk_megabytes }}
+        {% else %}
+          {{ ''|placeholder }}
+        {% endif %}
+      </td>
+    </tr>
+  </table>
+</div>