Let an admin handle the task-group lifecycle

[tcompa]

The same "manage" option that a user has on their own task groups should be also exposed for admins in this page

As of 2.9.0a4 (to be released asap), fractal-server will include

POST /admin/v2/task-group/{task_group_id}/deactivate/
POST /admin/v2/task-group/{task_group_id}/reactivate/

while it does already include

GET /admin/v2/task-group/activity/

meaning that http://localhost:5173/v2/admin/task-groups/activities can be used the same way as http://localhost:5173/v2/tasks/activities.

[tcompa]

The corresponding fractal-server PR is

• Expose task-group deactivate/reactivate to admins fractal-server#2062

[tcompa]

Fractal-server 2.9.0a4 is now available.