Add domain_unlock nomulus command

This command is used by registry operators to apply registry locks to
domain names.

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Created by MOE: https://github.com/google/moe
MOE_MIGRATED_REVID=176577240

java/google/registry/tools/RegistryTool.java

@@ -112,6 +112,7 @@ public final class RegistryTool {
           .put("send_escrow_report_to_icann", SendEscrowReportToIcannCommand.class)
           .put("setup_ote", SetupOteCommand.class)
           .put("uniform_rapid_suspension", UniformRapidSuspensionCommand.class)
+          .put("unlock_domain", UnlockDomainCommand.class)
           .put("update_application_status", UpdateApplicationStatusCommand.class)
           .put("update_claims_notice", UpdateClaimsNoticeCommand.class)
           .put("update_cursors", UpdateCursorsCommand.class)