Add configurable escrow file import GCS bucket

-------------
Created by MOE: https://github.com/google/moe
MOE_MIGRATED_REVID=123760355

java/google/registry/config/RegistryConfig.java

@@ -91,6 +91,11 @@ public interface RegistryConfig {
    */
   public String getZoneFilesBucket();
 
+  /**
+   * Returns the Google Cloud Storage bucket for importing escrow files.
+   */
+  public String getEscrowFileImportBucket();
+
   /**
    * Returns {@code true} if TMCH certificate authority should be in testing mode.
    *

java/google/registry/config/TestRegistryConfig.java

@@ -67,6 +67,11 @@ public class TestRegistryConfig implements RegistryConfig {
     return getProjectId() + "-zonefiles";
   }
 
+  @Override
+  public String getEscrowFileImportBucket() {
+    return getProjectId() + "-escrow-import";
+  }
+
   @Override
   public boolean getTmchCaTestingMode() {
     return true;