Automatic naming for an imported list

When importing a list from a CSV file, we still have to write a name in the dedicated field:


We could fill this field by using the name of the CSV file. Consider this:

1. if the list name field is not empty, keep what exists
2. if the field is empty, fill with an auto-generated name

Rules for generation:

- prefix with `L_`
- max total length of the list name is 30 characters
- use the letters rules of the auto naming of Sequence, Question, etc. for the rest