Fixes #8398: Add ConfigParam.size to enlarge specific config fields

[markkuleinio]

Fixes: #8398

Adds ConfigParam.size attribute that can be used for enlarging the text input field for specific configuration parameters.

Also adds size="80" for those parameters that seems to benefit from longer input field.

Unfortunately my Django skills did not allow for using textareas for the banner fields, it was not a simple field=forms.Textarea change as it resulted as TypeError: __init__() got an unexpected keyword argument 'required' in

netbox/netbox/extras/forms/config.py

Line 27 in aff5588

param_fields[param.name] = param.field(**field_kwargs)

🤔

[jeremystretch]

Rather than restricting the available parameter to a specific size (which doesn't even apply to most form widgets), IMO it would be preferable to allow the specification of a widget instance with arbitrary parameters. For the banners specifically, I would expect we'd use Django's Textarea widget rather than just increasing the size of the TextInput.

Edit: Actually, this is already possible using the field_kwargs attribute:

    ConfigParam(
        name='BANNER_LOGIN',
        label='Login banner',
        default='',
        description="Additional content to display on the login page",
        field_kwargs={
            'widget': forms.Textarea()
        }
    ),

[jeremystretch]

Per my comment here, we don't need to add a size attribute: We can just specify the widget to employ in field_kwargs for the relevant fields.