Bug 6394: purchase order has French strings hard coded in

Bug 6394: purchase order has French strings hard coded in

On the purchase order it said 'publié par' - instead of 'published by'.

The layout files for PDF generation in basket groups contain lots of English
strings, this change makes the template more consistent.

Currently the files are not translatable. The only way is to add translated
files to your installation.

To test:
Print a basket group as PDF. Verify string is ok for both possible settings
of system preference OrderPdfFormat:
- pdfformat::layout3pages
- pdfformat::layout2pages

Signed-off-by: Nicole C. Engard <nengard@bywatersolutions.com>
Signed-off-by: Paul Poulain <paul.poulain@biblibre.com>