Improve code for views and controllers

[MestourBS]

Note: Likely contains some missing things

All controllers:

• $error is now loaded from form_validation
• Removed unused variables and models All views:
• Replaced $error with $this->form_validation->error_string()
• Use validation_errors() instead of prewritten errors, with a few exceptions
• Use form_input() and form_label() wherever possible
• Use $value ?? $default instead of isset($value) to reduce the calls
• Replace useless for with foreach
• Replace a line where something was searched in an array with a foreach to use array_search() Questionnaire:
• add() no longers returns a number for forms, use getNbQuestion()
• clozeTextPdf() no longer registers '[]' as a valid answer space Auth:
• login() no longer has a minimum username/password length. In case someone is registered from the database itself Topic:
• form_add_topic() and form_update_topic() have been replaced by form_validate_topic()
• Removed timezone usage in form_validate_module, nothing used it anyway
• Use a version of dropdown() similar to MY_Model for topics

[DidierViret]

Trop de conflits avec la branche Release 1.3. Refaire les changements en partant de la branche Release 1.3, discuter avec ViDi pour choisir quels changements doivent être faits dans les contrôleurs.