Scope down lastTransferTime to only ContactResource, DomainResource

and HostResource.

DomainApplication is not transferable and has no need for this
field. HostResource needs it because it can be transferred with
a domain.

This is all in service of removing the ofy().load() inside of
host's cloneProjectedAtTime.

-------------
Created by MOE: https://github.com/google/moe
MOE_MIGRATED_REVID=139346925

javatests/google/registry/flows/domain/DomainTransferRequestFlowTest.java

@@ -132,7 +132,7 @@ public class DomainTransferRequestFlowTest
 
   private void assertTransferApproved(HostResource host) {
     DateTime afterAutoAck = clock.nowUtc().plus(Registry.get("tld").getAutomaticTransferLength());
-    assertAboutEppResources().that(host)
+    assertAboutHosts().that(host)
         .hasCurrentSponsorClientId("NewRegistrar").and()
         .hasLastTransferTime(afterAutoAck).and()
         .doesNotHaveStatusValue(StatusValue.PENDING_TRANSFER);