PIM-1348 : use single table inheritance to store variant groups
PIM-1300 : add group type
PIM-1300 : add group type in group
PIM-1300 : add type column in group grid
PIM-1348 : add group type installer file and related data fixtures
PIM-1348 : move attribute group installer file
PIM-1348 : add basic group types
PIM-1348 : rename attribute group fixtures
PIM-1348 : rename attribute group and variant group expected files
PIM-1348 : refactor variant group to allow to import all kind of groups
PIM-1348 : remove old file and fixture
Merge branch 'master' into PIM-1348
PIM-1348 : update demo reference
PIM-1348 : add group type and fix variant group creation
PIM-1348 : fix variant scenario
PIM-1348 : add group type repository and a method to retrieve types by
used group entity
PIM-1348 : add type field in variant and group form types
PIM-1348 : add type field group and variant group creation view
PIM-1348 : add type field in group and variant group edit form type
Merge pull request #380 from akeneo/PIM-1348

[WIP] PIM 1348 : refactor group and variant group, add group type