Results 12 issues of David Blain

In the FTPSHook it's also possible to pass a buffer (like StringIO/BytesIO) instead of a path, I've refactored the retrieve_file and store_file methods in SFTPHook so those also support those...

area:providers
provider:sftp

As explained in my Airflow medium [blogpost](https://medium.com/apache-airflow/transfering-data-from-sap-hana-to-mssql-using-the-airflow-generictransfer-d29f147a9f1f), I've refactored the GenericTransfer to support deferred paginated reads. When dealing with large datasets, not the whole dataset needs to be read into...

area:providers
provider:common-sql
provider:standard