Feature Request: Allow setting the hashing used for lookup vindexes in CreateLookupVindex

[dbussink]

Feature Description

The CreateLookupVindex command does not allow overriding the hashing used for a lookup vindex on the backing lookup tables.

Use Case(s)

In #13955 we changed the default for integral types, but the same issue exists for string or binary types (which use MD5 based hashing by default atm, although to in a security context).

We could look at overriding the default, but in order to be safely migrate we also need to be able to have CreateLookupVindex support changing this.