[WIP] PIM-1325 : add history for groups and refactor changes detection

Bug fix: [yes|no]
Feature addition: [yes|no]
Backwards compatibility break: [yes|no]
Unit test passes: [yes|no]
Behat scenarios passes: [yes|no]
Checkstyle issues: [yes|no]*
Documentation PR: [link to the documentation PR if there is one]
Fixes the following jira:
- PIM-1325