Bug 17110: Lower CSRF expiry in Koha::Token

Bug 17110: Lower CSRF expiry in Koha::Token

Default expiry in WWW:CSRF is one week.
This patch sets it to 8 hours by default in Koha, and allows to
change the expiry period individually by passing MaxAge.

Test plan:
[1] Put items in your cart.
[2] Apply the example patch too.
[3] Send the cart from opac within the allotted 10 seconds.
[4] Send again, but wait some 10 seconds before submitting. Too late!

Tested 3 patches together, works as expected.
Signed-off-by: Marc Véron <veron@veron.ch>
Signed-off-by: Jonathan Druart <jonathan.druart@bugs.koha-community.org>
Signed-off-by: Mason James <mtj@kohaaloha.com>