Add support for exporting delta table to a permanent path instead of prefix with commit

[ion-elgreco]

Unfortunately I am not able to publish/register external tables myself in Databricks Unity Catalog. Therefore I need to be able to export the delta tables to one path permanently, so that the other team only has to register this once.

Instead of this:
https://<redacted>.blob.core.windows.net/lakefs-gold/_lakefs/exported/feat-delta-export-hook/94e6cc/<table>

I don't want the commit hash to be included in the path:
https://<redacted>.blob.core.windows.net/lakefs-gold/_lakefs/exported/feat-delta-export-hook/<table>

Ideally the delta exporter should only export the delta's of the log then.