4.x: Use H2 in-memory in SE archetype (helidon-io#7877)

* 4.x: Use H2 in-memory in SE archetype

* use jdbc:h2:mem

Author: romain-grecourt

archetypes/helidon/src/main/archetype/se/custom/database-output.xml

@@ -34,7 +34,7 @@
                     </list>
                     <value key="db-health-check-stmt" if="${health}">SELECT 0</value>
                     <list key="db-connection">
-                        <value><![CDATA[    url: "jdbc:h2:tcp://localhost:9092/~test"
+                        <value><![CDATA[    url: "jdbc:h2:mem:test;DB_CLOSE_DELAY=-1;DATABASE_TO_LOWER=TRUE"
     username: sa
     password:]]></value>
                     </list>