Add basic AllocationToken validation/redemption for domain creates

The next step is to add them for domain checks as well (which is simpler
because it doesn't involve validation).

This requires the addition of a TrimWhitespaceAdapter for XML JAXB objects,
which will prove useful for other @XmlValue attributes in the future.

-------------
Created by MOE: https://github.com/google/moe
MOE_MIGRATED_REVID=181526726

javatests/google/registry/xml/DateAdapterTest.java

@@ -25,6 +25,7 @@ import org.junit.runners.JUnit4;
 /** Unit tests for {@link DateAdapter}. */
 @RunWith(JUnit4.class)
 public class DateAdapterTest {
+
   @Test
   public void testMarshal() {
     assertThat(new DateAdapter().marshal(