Docs for SERVER-37080: Implement tuneable batch size for chunk migrations

Description

Description:

Document the new migrateCloneInsertionBatchSize and migrateCloneInsertionBatchDelayMS params alongside the corresponding rangeDeleterBatchSize (DOCS-12240)/rangeDeleterBatchDelayMS (DOCS-11809)

Engineering Ticket Description:

SERVER-27725 implemented batch inserts for chunk migrations, but for some workloads inserting a ~16MB batch can impact secondary read performance. This ticket would be to implement a tuneable parameter to control how many documents were inserted using the batch insert rather than inserting the entire batch at once.

Scope of changes

Impact to Other Docs

MVP (Work and Date)

Resources (Scope or Design Docs, Invision, etc.)