feat(techdemo): render issues with hemplate partials

req: examples/001

req: dx/008

req: list/003

req: form/002

examples/techdemo/templates/partials/issue_lane.heml

@@ -0,0 +1,7 @@
+<section +class="self.class" +data-lane="self.lane_id" +data-move-hid="self.move_handle" ondragover="slhxTechdemoDragOver(event)" ondragleave="slhxTechdemoDragLeave(event)" ondrop="slhxTechdemoDrop(event)">
+  <h3>{+ self.title +}</h3>
+  <p>{+ self.description +}</p>
+  <template h-for="card in &self.cards">
+    {+ card +}
+  </template>
+</section>