Bug 19794: Rename RLIST notice to SERIAL_ALERT to better reflect its purpose

Bug 19794: Rename RLIST notice to SERIAL_ALERT to better reflect its purpose

The RLIST sample notice is used to send an email to patrons who have
subscribed to be notified when a new issue for a subscription arrives.

This is a feature that is totally independent and not related to the
use of routing lists. In the GUI however, this was misleading so far.

- Rename  RLIST to SERIAL_ALERT and fixes the sample notices
- Fix explanations in the helf files
- Fix name of the module in letters from 'serials (routing list)'
  to 'serials (new issue)'

Note: There is no logic to be changed as the notice template
to be used is defined for each subscriptions and this is just
the sample notice. I've also opted against a database update, to not
interfere with existing installations, reports etc.

A patch to the manual will be submitted shortly after this passes QA.

Signed-off-by: Brendan Gallagher <brendan@bywatersolutions.com>
Signed-off-by: Josef Moravec <josef.moravec@gmail.com>
Signed-off-by: Jonathan Druart <jonathan.druart@bugs.koha-community.org>