Make all but one field on RegistryConfig static

The next step will be to get rid of RegistryConfig descendants and RegistryConfigLoader entirely.

-------------
Created by MOE: https://github.com/google/moe
MOE_MIGRATED_REVID=143812815

javatests/google/registry/export/ExportUtilsTest.java

@@ -15,6 +15,7 @@
 package google.registry.export;
 
 import static com.google.common.truth.Truth.assertThat;
+import static google.registry.config.ConfigModule.LocalTestConfig.RESERVED_TERMS_TEST_EXPORT_DISCLAIMER;
 import static google.registry.testing.DatastoreHelper.createTld;
 import static google.registry.testing.DatastoreHelper.persistReservedList;
 import static google.registry.testing.DatastoreHelper.persistResource;
@@ -56,7 +57,9 @@ public class ExportUtilsTest {
     createTld("tld");
     persistResource(Registry.get("tld").asBuilder().setReservedLists(rl1, rl2, rl3).build());
     // Should not contain jimmy, tine, or oval.
-    assertThat(ExportUtils.exportReservedTerms(Registry.get("tld")))
+    assertThat(
+            new ExportUtils(RESERVED_TERMS_TEST_EXPORT_DISCLAIMER)
+                .exportReservedTerms(Registry.get("tld")))
         .isEqualTo("This is a disclaimer.\ncat\nlol\nsnow\n");
   }
 }