User table - Default admin account

[geraldywy]

When grafana is first started up, it creates a default admin user. During migration, if the admin user has a changed password, the migration will ignore this fact since it already exists, and the primary key of id 1, will be silently ignored. I believe this library should also delete the first row in user table, similar to how the first row in org table is also deleted since these are default rows created, and a migration would more often than not expect to replace these rows?