Bug 20404: Turn on ExtendedPatronAttributes by default for new installations

Bug 20404: Turn on ExtendedPatronAttributes by default for new installations

Extended patron attributes are a very useful feature that should be
more obvious. We should activate them by default for new installations.

For testing:
- Run the web isntaller on an empty database
- Check that after installation ExtendedPatronAttributes is turned on

Signed-off-by: Charles Farmer <charles.farmer@inLibro.com>
Signed-off-by: Jonathan Druart <jonathan.druart@bugs.koha-community.org>