Recalculate additional CI minutes lazily on a monthly basis

Objectives

On the 1st of the month, recalculate the remaining purchased minutes based on the previous month's usage. This should occur when we lazily create new records for Ci::Minutes::NamespaceMonthlyUsage.

Technical Approach

We currently recalculate remaining additional/purchased CI minutes in bulk. The logic is the same but needs to be done for the single namespace being lazily reset.

• If the minutes consumption is greater than the monthly limit (ci_namespace_monthly_usage.amount_used > namespaces.shared_runners_minutes_limit) (or default limit from Gitlab::CurrentSettings) and namespace has any additional minutes available (namespaces.extra_shared_runners_minutes_limit > 0)
• Then, update namespaces.extra_shared_runners_minutes_limit as the difference between the minutes consumption minus the sum of monthly minutes limit and additional minutes.
• Do that only if the feature flag ci_use_new_monthly_minutes is enabled, to avoid double reset of extra_shared_runners_minutes_limit
• Skip the recalculation of extra_shared_runners_minutes_limit in Ci::Minutes::BatchResetService if the feature flag ci_use_new_monthly_minutes is enabled.