Add use_turbo configuration with default to false.

[gobijan]

This PR enables Rails 7 and Devise to work out of the box. Devise now opts out of turbo by default for its forms by making use of data: { turbo: Devise.use_turbo} setting on forms.

I've seen this PR https://github.com/heartcombo/devise/pull/5487 but it is not configurable and hardcoded. So people that have opted into turbo can do this via a setting (maybe they fixed notifications by patching devise etc.). I went with an approach that conforms to the style I've seen by inspecting the devise codebase.

My PR defaults to not using turbo in devise forms by default. I know this is a minor breaking change for people that might have patched the problem otherwise but it's the way to offer a sane default experience with Devise and Rails 7 until the maintainers decide on a real solution.