New form field for toggle inputs

[Hristo Trendafilov]

Toggle inputs are quite common web elements and are widely used in modern web pages, CSS frameworks, etc.

Those could be narrowed down to the BooleanField but with several key differences:

• They never be required, even if defied like so;
• They should always return cleaned data to be False if not passed in the form data;
• They should always have an initial value of False unless explicitly defined;
• They have a special widget, based on the CheckboxInput, but adding role="switch" and aria-checked="false/true"/based on the value/;