fdo#39944: Fix mapping for some a11y roles to ATK

In particular, EDIT_BAR, EMBEDDED_OBJECT and HYPER_LINK were being
mapped to custom roles when specific roles exist; fixed passing the
proper name to registerRole.

Besides, moved two roles that were in the section 'don't exist in ATK
yet' because that's not the case now.

Change-Id: I6818a0ac623f45053812b5c6dd5fc25c9abf4f65