WIP: Feature/migrate cleans up transactions from documents
As requested here, add the removal of transactions information from inside the normal documents.
Note that:
- This has impact on migration retries. When transaction data starts being deleted from normal documents, if the migration is interrupted for some reason, it will not be possible to reconstruct the transaction log anymore, and further retries will fail for different reasons.
- I have not tested this on any set of databases.
- Migration will take considerably longer as it will now have to go through all documents in the database to modify them.