Remove models.base.Model.validate(), manipulator field functions, validator lists

[Malcolm Tredinnick]

With the model-aware validation being pushed to after 1.0, we should ensure nobody uses code that is intentionally in a broken or unsupported state. This means

• Removing django.db.models.base.Model.validate(), since it's always been incomplete and not to be used. But still people try using it. It's not part of the public API at the moment.
• Removing code in django.db.models.fields that is only to support manipulators. They are only oldforms-admin related.
• Removing validator lists from field classes, since they're again only oldforms-admin related.

This probably goes after removing oldforms (#7742) to get the ordering right for people still using oldforms + manipulators.

[Gary Wilson]

Replying to mtredinnick:

• Removing code in django.db.models.fields that is only to support manipulators. They are only oldforms-admin related.
• Removing validator lists from field classes, since they're again only oldforms-admin related.

I'm rolling both of these into #7742, as they are oldforms-related but will need to stick around until the rest of Django is oldforms-free.

[Gary Wilson]

(In [8348]) Fixed #8206 -- Removed validate methods of Model and Model fields. They are are unsupported for 1.0 and will be replaced with more complete model validation (refs #6845).

[Jacob]

Milestone 1.0 beta deleted