Bug 20144: [sql_modes] Fix datatype for aqbasket.authorisedby

Bug 20144: [sql_modes] Fix datatype for aqbasket.authorisedby

It's defined as a VARCHAR(10) in DB, but it is expecting a
borrowernumber instead

Fix for
Data too long for column 'authorisedby'

Must be a FK but first a borrowernumber
Need to update kohastructure for the comment?

Signed-off-by: Josef Moravec <josef.moravec@gmail.com>
Signed-off-by: Julian Maurice <julian.maurice@biblibre.com>
Signed-off-by: Jonathan Druart <jonathan.druart@bugs.koha-community.org>