Max length of notes should be fixed

[minimalparts]

When the user adds a resource to the instance, or when they click on the comment button on a specific URL, they can add a manual note to the resource. The length of this note is currently odd: too short and inconsistent (different max length in the database model and the WTF forms, perhaps also at display time). To fix in app/api/models.py as well as app/forms.py (other places too?)