Bug 13968 - Branch email hints are misleading

Bug 13968 - Branch email hints are misleading

This patch replaces missleading notes with Reply-To and Return-Path fields
to reflect indicate falback values if they are empty (ReplyToDefault and
ReturnpathDefault system prefs).

To test:
- Apply patch
- In Home > Administration > Libraties and Groups, edit a library
- Verify that hints display for fields Reply-To and Return-Path, indicating
  their default values.

Amended to remove extra </li> - 2017-02-21 mv

Signed-off-by: Mark Tompsett <mtompset@hotmail.com>
Signed-off-by: Jonathan Druart <jonathan.druart@bugs.koha-community.org>
Signed-off-by: Kyle M Hall <kyle@bywatersolutions.com>