Add error code for SAP Hana

This commit adds a SQLErrorCodes instance for SAP DB, based on a
contribution from Andrew Clemons

Mostly based on SAP Hana SPS 07 with a few additional codes that are
only present is previous versions:

* -813 - Cannot connect to host somehost:30115 [Connection refused]
* -709 - Unknown host somehost:30115 [somehost], -709.]
* -708 - Cannot connect to jdbc:sap://somehost:30115 [Receive of connect failed.]
* -11210 - Invalid column index XYZ.

Issue: SPR-11770