Bug 33606: Add a erm/config route to retrieve the ERM config needed for the Vue app

Bug 33606: Add a erm/config route to retrieve the ERM config needed for the Vue app

This could be extended later in bug 32968 to pass the permission of the
logged in user.

Signed-off-by: Pedro Amorim <pedro.amorim@ptfs-europe.com>
Signed-off-by: Marcel de Rooy <m.de.rooy@rijksmuseum.nl>
(cherry picked from commit cda3c377a20c401ef9a755f24eb839d515a8af72)
Signed-off-by: Fridolin Somers <fridolin.somers@biblibre.com>
(cherry picked from commit 5078f9f4dff2788318bee544e00724fa2fbf1dad)
Signed-off-by: Matt Blenkinsop <matt.blenkinsop@ptfs-europe.com>