We won't run:
- old pre auth-v1 migration code
- code creating auth-v1 tables
We will keep running:
- code creating default rows
- code creating auth-v1 keyspace (needed due to cqlsh legacy hack,
it errors when executing `list roles` or `list users` if
there is no system_auth keyspace, it does support case when
there is no expected tables)
Fixes https://github.com/scylladb/scylladb/issues/17737Closesscylladb/scylladb#17939
* github.com:scylladb/scylladb:
auth: don't run legacy migrations on auth-v2 startup
auth: fix indent in password_authenticator::start
auth: remove unused service::has_existing_legacy_users func