* Move Terms & Conditions, CoC into Intro slide of onboarding
Closes https://github.com/thepracticaldev/dev.to/issues/6545.
* Rename ClosingSlide in Onboarding tests
* Rename EmailListTermsConditionsForm to EmailPreferencesForm
* Proper lint and prepend `v2:` to some onboarding components
* Move email preferences to last slide
Closes https://github.com/thepracticaldev/dev.to/issues/6550.
* Use crayons variables for padding
* Remove backToSlide function, rename buttonIsDisabled function
