Feat: add Terms of Use update view and middleware

[MyPyDavid]

Description

Related issue: #141, #161

It adds a migration for the ConsentFieldValue model: accounts.0022_add_created_updated_to_consent
So it requires a python manage.py migrate.
I have added some methods that handle the consent and session to the model.

configuration in the rdmo-app

When ACCOUNT_TERMS_OF_USE is enabled, some settings need to be configured in the rdmo-app as well.

In the settings from local.py:

if ACCOUNT_TERMS_OF_USE:
    MIDDLEWARE += [
        'rdmo.accounts.middleware.TermsAndConditionsRedirectMiddleware'
    ]

An optional feature is added that sets the date on which the ToU text is valid, so that it can be easily updated when the text might change. The optional setting is TERMS_VERSION_DATE and needs to be a valid date string that is compatible with formats from django get_format('DATE_INPUT_FORMATS'). The date of this setting checks if the user has updated their consent on or after that date, otherwise the consent is invalid and asked to accept again.

# for example
TERMS_VERSION_DATE = "2025-12-30"

Optionally, in the urls.py:

if settings.ACCOUNT_TERMS_OF_USE:
    from rdmo.accounts.views import terms_of_use, terms_of_use_accept
    urlpatterns += [
        path("account/terms-of-use/accept/", terms_of_use_accept, name="terms_of_use_accept"),
        path("account/terms-of-use/", terms_of_use, name="terms_of_use"),
    ]

Motivation and Context

How has this been tested?

Screenshots (if appropriate)

[MyPyDavid]

can be reviewed when tests pass