Fix #9590. Fix #9612.

For external storage with lots of parameter settings (>4), wrap the content of the cell to let a full view of the parameters.
The rows of the table are now always visible until the end (the trash icon is accessible).
(Note : A strange 3px margin forces me to add a class on the row added by javascript, to be able to align them with the rows rendered by the server.)
CSS code style: One declaration per line please, so this should be:
```
#externalStorage td.configuration,
#externalStorage td.backend {
```