Bug 35570: Revert some strings translatability

Bug 35570: Revert some strings translatability

This patch reverts making core field descriptions translatable. It was
an obvious move and a needed one. But it turns out our core templates
are using those keys ('Author' and 'Title' in particular) and as such
translating them would break display (at least in the OPAC). Without
this patch, the ILL requests table in the OPAC doesn't display the title
and author columns values (i.e. displays 'N/A' instead)

Added a FIXME in the code, and will file a bug soo we fix this properly.

Signed-off-by: Tomas Cohen Arazi <tomascohen@theke.io>
Signed-off-by: Katrin Fischer <katrin.fischer@bsz-bw.de>