Migrate Domain, Registrar, and Token models to java.time (#3022)

Migrated core EppResource and Token models from Joda-Time DateTime to java.time.Instant.

Specific migrations include:
- `DomainBase` and `Domain`: Migrated `registrationExpirationTime` and various other timestamps to use `Instant` directly.
- `Registrar`: Migrated `lastPocVerificationDate` and certificate dates to `Instant`.
- `BulkPricingPackage`: Migrated `nextBillingDate` and `lastNotificationSent`.
- `AllocationToken`: Migrated `tokenStatusTransitions` map keys to `Instant`.
- `LaunchNotice`: Migrated `acceptedTime` and `expirationTime`.

Updated all associated EPP flows (e.g., DomainCreateFlow, DomainRenewFlow), batch actions (e.g., CheckBulkComplianceAction, DeleteExpiredDomainsAction), command-line tools (e.g., UnrenewDomainCommand, UpdateBulkPricingPackageCommand), and tests to handle `Instant` directly.

common/src/main/java/google/registry/util/DateTimeUtils.java

@@ -170,7 +170,7 @@ public abstract class DateTimeUtils {
    * Adds years to a date, in the {@code Duration} sense of semantic years. Use this instead of
    * {@link java.time.ZonedDateTime#plusYears} to ensure that we never end up on February 29.
    */
-  public static Instant plusYears(Instant now, long years) {
+  public static Instant plusYears(Instant now, int years) {
     checkArgument(years >= 0);
     return (years == 0)
         ? now