PIM-2290: Remove data_identifier property from datagrid configuration
PIM-2290: Redefine Delete mass action
PIM-2290: Remove data_identifier from datagrid definition
PIM-2290: Clean mass actions
PIM-2290: Update spec
PIM-2290: Update CHANGELOG.md
Merge branch 'master' into data_identifier

Conflicts:
	CHANGELOG.md
Merge pull request #922 from akeneo/data_identifier

PIM-2290: Remove data_identifier parameter for mass actions