PIM-2716 : allow to define many roles and groups when load new users
PIM-2716 : add a datafixture for groups
PIM-2716 : add a roles installer
PIM-2716 : update roles and groups loaders
PIM-2716 : update minimal set and roles fixtures loader to setup ACLs
PIM-2716 : Load our own users, groups and roles instead of Oro's
PIM-2716 : fix user groups
PIM-2716 : update other installer fixtures
PIM-2716 : update changelog
Merge pull request #1190 from akeneo/PIM-2716-update_data_fixtures

PIM-2716 : enhance installer data fixtures