Bug 34339: (bug 33556 follow-up) Easy ERM-related changes

Bug 34339: (bug 33556 follow-up) Easy ERM-related changes

I left the (easy) ERM cases out because it throws this when running the
QA script:

Processing files before patches
|========================>| 51 / 51 (100.00%)

An error occurred : Inconsistent hierarchy during C3 merge of class 'Koha::REST::V1::ERM::EHoldings::Titles::Local':
	current merge results [
		Koha::REST::V1::ERM::EHoldings::Titles::Local,
	]
	merging failed on 'Mojolicious::Controller' at /kohadevbox/qa-test-tools/koha-qa.pl line 112.

and didn't want this to pollute the rest of the changes.

Signed-off-by: Martin Renvoize <martin.renvoize@ptfs-europe.com>
Signed-off-by: Tomas Cohen Arazi <tomascohen@theke.io>
Signed-off-by: Marcel de Rooy <m.de.rooy@rijksmuseum.nl>
Signed-off-by: Tomas Cohen Arazi <tomascohen@theke.io>