Create a separate billing event when EAP is applied

When EAP is involed we current have one billing event for domain create that
has the create fee and EAP fee lumped together. Change it to record two
separate billing events for each.

-------------
Created by MOE: https://github.com/google/moe
MOE_MIGRATED_REVID=132335349

java/google/registry/model/domain/fee/BaseFee.java

@@ -15,6 +15,7 @@
 package google.registry.model.domain.fee;
 
 import static com.google.common.base.MoreObjects.firstNonNull;
+import static com.google.common.base.Preconditions.checkState;
 
 import google.registry.model.ImmutableObject;
 import google.registry.xml.PeriodAdapter;
@@ -38,6 +39,24 @@ public abstract class BaseFee extends ImmutableObject {
     @XmlEnumValue("delayed")
     DELAYED
   }
+  
+  /** Enum for the type of the fee. */
+  public enum FeeType {
+    CREATE("create"),
+    EAP("Early Access Period, fee expires: %s"),
+    RENEW("renew"),
+    RESTORE("restore");
+
+    private final String formatString;
+
+    FeeType(String formatString) {
+      this.formatString = formatString;
+    }
+
+    String renderDescription(Object... args) {
+      return String.format(formatString, args);
+    }
+  }
 
   @XmlAttribute
   String description;
@@ -54,6 +73,9 @@ public abstract class BaseFee extends ImmutableObject {
 
   @XmlValue
   BigDecimal cost;
+  
+  @XmlTransient
+  FeeType type;
 
   public String getDescription() {
     return description;
@@ -81,6 +103,15 @@ public abstract class BaseFee extends ImmutableObject {
   public BigDecimal getCost() {
     return cost;
   }
+  
+  public FeeType getType() {
+    return type;
+  }
+
+  protected void generateDescription(Object... args) {
+    checkState(type != null);
+    description = type.renderDescription(args);
+  }
 
   public boolean hasDefaultAttributes() {
     return getGracePeriod().equals(Period.ZERO)