Bug 12749 - Better translatability for list module

Bug 12749 - Better translatability for list module

This patch changes wording of explanations in list module to make them better translatable.
Additionally, it removes explanation for "Open list" from help screen, because this choice is not available.

To test:
Go to Home > Lists > Public lists > Create new list
Verify that the text changed to "Private list:..." rsp. "Public list:..." in right part of screen and on help screen.

Signed-off-by: Chris Cormack <chris@bigballofwax.co.nz>
Signed-off-by: Marcel de Rooy <m.de.rooy@rijksmuseum.nl>
Signed-off-by: Tomas Cohen Arazi <tomascohen@gmail.com>