Bug 11906: ensure that Koha::Database uses UTF8 mode when connecting to databases

Bug 11906: ensure that Koha::Database uses UTF8 mode when connecting to databases

This patch fixes an issue whereby the DBIx::Class schema objects
were not connecting to the underlying database in UTF8 mode.  This
most visibility manifested as patron list pages not displaying
diacritics correctly.

To test:

[1] Create a patron list, and make sure that it contains at least
    one patron whose name or patron category description contains
    a non-ASCII character.
[2] View the list contents; the diacritics should appear mangled.
[3] Apply the patch.
[4] View the patron list again.  This time, the diacritics should
    be displayed correctly.  Note that Apache will also log
    "list.pl: Wide character in print ...", but this is the lesser
    of two evils.
[5] Verify that prove -v t/db_dependent/Koha_Database.t passes.
[6] (extra credit) Verify that  t/db_dependent/Koha_Database.t
    passes when connect to a PostgreSQL database.

Signed-off-by: Galen Charlton <gmc@esilibrary.com>
Signed-off-by: Chris Cormack <chrisc@catalyst.net.nz>
Signed-off-by: Jonathan Druart <jonathan.druart@biblibre.com>
Signed-off-by: Galen Charlton <gmc@esilibrary.com>
(cherry picked from commit 05a6beba9f023f87d3355b6e72f35b220cd691b0)
Signed-off-by: Fridolin Somers <fridolin.somers@biblibre.com>