Add unlock fields to RegistryLocks (#408)

* Add unlock fields to RegistryLocks

This will make it easier to reason around inter-connected registry lock
objects (like when we add dependent roids). It will make it easier to
answer the question of "Have all locks associated with this host/contact
roid been unlocked?", as well as the question of "Was the last lock
object associated with this domain unlocked?"

* Responses to CR

* Make the DAO API more specific

* whoops, undo rename

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

@@ -148,14 +148,16 @@
 
     create table "RegistryLock" (
        revision_id  bigserial not null,
-        action text not null,
-        completion_timestamp timestamptz,
-        creation_timestamp timestamptz not null,
         domain_name text not null,
         is_superuser boolean not null,
+        last_update_timestamp timestamptz,
+        lock_completion_timestamp timestamptz,
+        lock_request_timestamp timestamptz not null,
         registrar_id text not null,
         registrar_poc_id text,
         repo_id text not null,
+        unlock_completion_timestamp timestamptz,
+        unlock_request_timestamp timestamptz,
         verification_code text not null,
         primary key (revision_id)
     );