Improve delete queries by separating the data extraction from actual delete.
Extraction is made with a configurable limit, using --limit flag, then deletes are made in batch mode with a configurable batch size, using --batch-size flag.
Default value for limit is 100000 records and default value for batch size is 100 records.

This uses LEFT JOIN to select also login and consent requests which
did not result in a complete authentication, i.e. user requested login
but timed out or user logged in and timed out at consent.

This splits in two independent SELECTs the extraction of login and consent
requests eligible for deletion. This solves a bug in the single SELECT
causing deletion of consent requests where matching login requests were
eligible for deletion and vice versa. With independent SELECTs we keep
consent requests even if matching login request gets deleted and vice
versa.

This adds a check in janitor command handler to ensure that user is not
passing wrong values for limit anch batch flags. This also adds tests
for these command line arguments.

This fix avoids unexpected behaviors if the janitor cli is executed in parallel. In that case, if we do not order records to delete, we might incur in duplicate deletes.