Maximum characters for questionnaire text answers

**Is your feature request related to a problem? Please describe.**

It would be useful to set a character limit on questionnaire answers to provide guidance for users regarding how long their answers should be.

**Describe the solution you'd like**

To have a number input field next to each question in the admin, labeled "Character limit", by default set to zero (no limit), which determines the maximum characters the user answers to those questions can have.

**Describe alternatives you've considered**

Another possibility could be to define this globally for the questionnaire, setting the character limit for each type of question.

**Additional context**

-

**Could this issue impact on users private data?**

No

**Funded by**

Fundació Bosch i Guimpera