Add extensible custom logic to the domain renew flow

This also adds a TODO in DomainCheckFlow to document the fact that as-of date is not overridden when passed to the custom logic.

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Created by MOE: https://github.com/google/moe
MOE_MIGRATED_REVID=140031318

java/google/registry/flows/custom/CustomLogicFactory.java

@@ -50,4 +50,9 @@ public class CustomLogicFactory {
       EppInput eppInput, SessionMetadata sessionMetadata) {
     return new DomainUpdateFlowCustomLogic(eppInput, sessionMetadata);
   }
+
+  public DomainRenewFlowCustomLogic forDomainRenewFlow(
+      EppInput eppInput, SessionMetadata sessionMetadata) {
+    return new DomainRenewFlowCustomLogic(eppInput, sessionMetadata);
+  }
 }