Add composite asset support with creation and descriptor handling

src/main/resources/templates/create_asset.html

@@ -2,6 +2,7 @@
 <div th:fragment="content">
 	<h2>Create a <span th:text="${descriptor.displayName}"></span></h2>
 	<form th:action="'/'+${(action == 'duplicate') ? 'create' : action}+'/'+${(asset != null && action != 'duplicate') ? asset.getQr() : descriptor.getType()}" method="post">
+		<input th:each="t : ${types}" type="hidden" name="type" th:value="${t}"/>
 		<div th:each="d : ${descriptors}">
 			<h2 th:text="${d.displayName}"></h2>
 			<table border="1" cellpadding="4">