Update doc for OPENDJ-6879

The patch for OPENDJ-6879, https://stash.forgerock.org/projects/OPENDJ/repos/opendj/pull-requests/5043 , brings changes to the REST to LDAP configuration that must be documented.

• The "resourceTypeProperty" has been removed. The value is inferred from the property that has "type": "resourceType".
• A new "allowedAuxiliaryTypes" array (list), default: empty, should be added to https://ea.forgerock.com/docs/ds/rest-guide/index.html#rest-resource-type-properties . This list specifies auxiliary LDAP objectClass types of the underlying LDAP entries that the resources are mapped to. If the concrete auxiliary object classes all derive from an abstract auxiliary object class, it is sufficient to list the abstract object class rather than enumerating the whole list. For example, ["ds-pwp-validator"] covers the password validator object classes.