MD: Support selecting specific batches for inclusion in the audit

[arsalansufi]

Open question from Slack re motivation:

is MD's hope to guarantee that a certain batch is included in the audit? So if the RLA math selects it great, nothing to add. But if it doesn't, it'll get added in as an extra?

[nikhilb4a]

Relates to how in Georgia we already add batches to meet their heuristic i.e. at least one hmpb batch. Long term we may want a generalized UI solution that supports the Georgia case and this MD case.