Cache history values for RDAP domain requests (#2777)

In RDAP, domain queries are the most common by a factor of like 40,000
so we should optimize these as much as possible. We already have an EPP
resource / foreign key cache which does improve performance somewhat but
looking at some sample logs, it only cuts the RDAP request times by like
40% (looking at requests for the same domain a few seconds apart).

History entries don't change often, so we should cache them to make
subsequent queries faster as well. In addition, we're only caching two
fields per repo ID (modification time, registrar ID) so we can cache
more entries than we can for the EPP resource cache (which stores large
objects).

core/src/test/java/google/registry/rdap/RdapJsonFormatterTest.java

@@ -462,12 +462,12 @@ class RdapJsonFormatterTest {
   }
 
   @Test
-  void testGetLastHistoryEntryByType() {
+  void testGetLastHistoryByType() {
     // Expected data are from "rdapjson_domain_summary.json"
     assertThat(
             Maps.transformValues(
-                rdapJsonFormatter.getLastHistoryEntryByType(domainFull),
-                HistoryEntry::getModificationTime))
+                RdapJsonFormatter.getLastHistoryByType(domainFull),
+                RdapJsonFormatter.HistoryTimeAndRegistrar::modificationTime))
         .containsExactlyEntriesIn(
             ImmutableMap.of(TRANSFER, DateTime.parse("1999-12-01T00:00:00.000Z")));
   }