Support VARBINARY for uuids

[kasium]

No description provided.

[jarus]

LGTM beside the pending CI verification but I assume that should be gone once #302 has been merged.

Maybe two things for further enhancements:

1. How about documenting the usage with SAP HANA's NEWUID and SYSUUID?
2. How about adding another switch use_fastuuid so that SQLAlchemy-HANA returns a fastuuid.UUID object?

[kasium]

1. How about documenting the usage with SAP HANA's NEWUID and SYSUUID?

will do that

2. How about adding another switch use_fastuuid so that SQLAlchemy-HANA returns a fastuuid.UUID object?

I would prefer a general solution which should be implemented in SQLAlchemy since we just extend the Uuid type. Let me open a discussion there: sqlalchemy/sqlalchemy#11683