Make the relationship types more generic especially to avoid issue
with community-designed standards that might change later the types,
broke compatibility or decide to change their mind due to some
proprietary vendors trying to lock-in the users.
Relationship type can be from existing STIX 2.0 ones, MISP
relationships or other proposed by the community. Please be
careful that a relationship type can influence the ability
of export of MISP events if the type is not supported by
the target format.