Move 'snippet' queries to 'snippets' folders

cpp/ql/examples/snippets/volatilevariable.ql

@@ -0,0 +1,12 @@
+/**
+ * @name Variable declared volatile
+ * @description Finds variables with a `volatile` modifier
+ * @tags variable
+ *       volatile
+ */
+
+import cpp
+
+from Variable f
+where f.isVolatile()
+select f