Relax host-release's id restriction from wildfly-config XSD

The wildfly-config XSD defines the host-releaseType XML type whose id attribute is a string corresponding to WildFly and EAP versions (with a comment on the matching management versions).

Whenever a new release of WildFly or EAP, we must update the schema to include this new version in the enum constraint. This in turn, requires to bump the XSD version and updates all the XML files that references it.

This is not necessary.

The XSD is not used when we start WildFly or EAP. The code that will read the host-releaseType's id type is in the KnownRelease enum which also defines the mapping between WildFly/EAP versions and their management versions (https://github.com/jmesnil/wildfly-core/blob/f31a55e1ecdf6bbfb6d095d2f887be247e952c7e/host-controller/src/main/java/org/jboss/as/domain/controller/resources/HostExcludeResourceDefinition.java#L61).

Removing the enumeration restriction on this id attribute will prevent artificial bumps of wildfly-config XSD every time a new version of EAP and WildFly is released.