[X] edit Group entity
[X] allow to associate an Archive
[X] DB
[X] UX
[X] Backend save
[X] allow to associate a Category
[X] DB
[X] UX
[X] Backend save
[X] allow to associate some Tags
[X] DB
[X] UX
[X] Backend save
[X] Edit POI creation page to inherit these settings
[X] Archive
[X] Category
[X] Tags
[ ] Edit Media/News creation page to inherit these settings
[X] → WONTFIX: Media and News, without any Tag, will inherit the POI's Tags as default.