adding dev preview note draft

Author: aireilly

snippets/developer-preview.adoc

@@ -0,0 +1,11 @@
+// DO NOT USE THIS SNIPPET. DEVELOPER PREVIEW FEATURES ARE NOT DOCUMENTED IN CORE OPENSHIFT DOCS.
+
+// When including this file, ensure that {FeatureName} is set immediately before the include. Otherwise it will result in an incorrect replacement.
+
+[IMPORTANT]
+====
+[subs="attributes+"]
+{FeatureName} is a Developer Preview feature only. Developer Preview features are not supported by Red Hat in any way and are not functionally complete or production-ready. Do not use Developer Preview features for production or business-critical workloads. Developer Preview features provide early access to upcoming product features in advance of their possible inclusion in a Red Hat product offering, enabling customers to test functionality and provide feedback during the development process. These features might not have any documentation, are subject to change or removal at any time, and testing is limited. Red Hat might provide ways to submit feedback on Developer Preview features without an associated SLA.
+====
+// Undefine {FeatureName} attribute, so that any mistakes are easily spotted
+:!FeatureName: