cli: add user-promo flag to add data in user_promo_codes table

Exalate commented:


https://github.com/cockroachdb/cockroach/pull/61531 --- Release note (cli change): add option in demo movr command to populate user_promo_code table  Signed-off-by: Tharun <rajendrantharun@live.com>

Jira Issue: DOC-1184