Bug: Ignore accents and diacritics in search

[smadbe]

Overview

As the usual user, if you try to add content to a chapter and you look for "College" you find " Collège Prépa Algorea " while if you look for "Collège", you do not find it.

So we should remove the accents and diacritics for strings sent to search.

Acceptance criteria

• [ ] For both item and group children search:
• [ ] Remove accents and diacritics to the search services (see https://stackoverflow.com/a/37511463/759432)