Make toolbar responsive

pdureau → credited vanessa.fayard → .

According to @vanessa.fayard we must stay in Flex instead of switching to Grid, and play with the order of elements: the middle part is moved to third position.

Using container queries for responsive.

2 rows on small screens, if container is less than 850px:

• one row for only the tabs, centred
• one row for the left & right buttons

Works on Firefox & Chrome

Thanks, I will have a look

Thanks for the work, but the style is not good, would be great to make it pass.

I merged because :

- I got no errors but 2 warnings
- Only one of those warnings was about the file modified in this MR

But I will take care of this

Style fixed.