feat(sql): Add history table for iam_user

This adds a history table for `iam_user`.

internal/db/schema/migrations/oss/postgres/80/03_iam.up.sql

@@ -37,4 +37,30 @@ begin;
   select public_id, name, description, type, parent_id, primary_auth_method_id
     from iam_scope;
 
+  create table iam_user_hst (
+    public_id wt_user_id not null,
+    name text null,
+    description text null,
+    scope_id wt_scope_id not null,
+    history_id wt_url_safe_id default wt_url_safe_id() primary key,
+    valid_range tstzrange not null default tstzrange(current_timestamp, null),
+    constraint iam_user_hst_valid_range_excl
+      exclude using gist (public_id with =, valid_range with &&)
+  );
+  comment on table iam_user_hst is
+    'iam_user_hst is a history table where each row contains the values from a row '
+    'in the iam_user table during the time range in the valid_range column.';
+
+  create trigger hst_on_insert after insert on iam_user
+    for each row execute function hst_on_insert();
+  create trigger hst_on_update after update on iam_user
+    for each row execute function hst_on_update();
+  create trigger hst_on_delete after delete on iam_user
+    for each row execute function hst_on_delete();
+
+  insert into iam_user_hst
+    (public_id, name, description, scope_id)
+  select public_id, name, description, scope_id
+    from iam_user;
+
 commit;