Alignment with fractal-server 2.9.0

[zonia3000]

Checklist before merging

• I added an appropriate entry to CHANGELOG.md

Closes #638
Closes #639

[tcompa]

First examples

[tcompa]

Minor issues

This should not read "Task collection", because it could be a deactivation or reactivation. We can simply use "Task-group activity logs".

I would slightly modify this one.

1. Display a text like "The task group is currently active" (or "not active").
2. If it's active: show a button like "Deactivate task group". When this is clicked, ask for confirmation (with the same warning as now).
3. If it's not active: show a button like "Reactivate task group"

[tcompa]

As some sort of end-to-end test: I confirm that after a full collect-deactivate-reactivate cycle I can properly use the tasks in a workflow

[zonia3000]

Deactivate:

Reactivate: