This introduces a new djblets.privacy.consent.forms module, which

features fields, widgets, and form mixins for prompting for consent.

Along with the rest of the consent functionality, it's now very easy

for applications to offer users options on how to manage their own

personal data.
ConsentRequirementField (and its corresponding widget) displays an

informative field for a single ConsentRequirement. It clearly lists

a summary of the requirement, an optional icon representing it, a

description of the intended usage, and a description of what data would

be sent. Two buttons, "Allow" and "Block," are available to allow usage

of their private data for the feature or to block usage.
MultiConsentRequirementsField wraps multiple

ConsentRequirementFields, one for each requirement provided (or one

for each one registered in the registry). This is intended for forms

that want to offer all (or many) options at once.
ConsentFormMixin can be mixed into other forms, and will construct a

MultiConsentRequirementsField on initialization. It provides a handful

of methods to override for controlling data going into the field, and a

save_consent() method to save and record the choices made.
ConsentConfigPageFormMixin is used for configforms, and provides

default implementations of the methods needed by ConsentFormMixin. It

also automatically handles the saving, and adds a message to display

on the form when saved. This is the easiest way to provide consent

information to users.

Unit tests pass.
Manually and thoroughly tested this form, allowing and blocking

consent for multiple options and testing results. Tested validation

logic and resulting data in the database on success.