Verify user phone in the registration

See issue #157 Our PRD design https://gitlab.com/gitlab-jh/gitlab/-/issues/155

This feature is JH SaaS only, new user need to verify phone by sms code. The feature works for now , it looks like

@godfat-gitlab Could you please help review this MR first and give some advice, since I am struggling with:

• which code should be put in jh and which not
• this feature cause serveral spec tests failed since the registration feature is coupled with upstream, how to deal with them

Thanks!