8.0 : Add module hr_expense_analytic_default

This PR is the equivalent for v8 of the following PR for v7: https://github.com/OCA/hr/pull/44
Please comment on the PR for v7 (unless your remark is specific for v8)
Yeah, now I understand your motivation. Good approach. Maybe a label in screen helps to explain its use for noobs like me :stuck_out_tongue: