Add a relockDuration to the RegistryLock SQL object (#514)

* Add a relockDuration to the RegistryLock SQL object

This is the length of time after an unlock that we will re-lock the
domain in question.

* Sort by domain name for stability

Note: this is likely not the best solution for the UI but we can iterate
on this.

* Add nullable

* Add a converter for Duration

db/src/main/resources/sql/schema/db-schema.sql.generated

@@ -176,6 +176,7 @@
         lock_request_timestamp timestamptz not null,
         registrar_id text not null,
         registrar_poc_id text,
+        relock_duration int8,
         repo_id text not null,
         unlock_completion_timestamp timestamptz,
         unlock_request_timestamp timestamptz,