[OSIS-3473] adapt excel syle
[OSIS-3473] adapt excel syle

-Adjust column operator width
-Color in green and operator

	modified:   base/business/education_groups/excel.py

uclouvain/OSIS-Louvain,uclouvain/osis,uclouvain/osis,uclouvain/osis,uclouvain/OSIS-Louvain,uclouvain/OSIS-Louvain,uclouvain/osis