Frontend login flow update

[maciej-jaworski]

child of #1126

Related to #1478

Start working from 1478-partner-registration branch

• [x] Add a frontend route /login/token?key={param} which will serve as an alternative to login
• [x] Adjust the login flow - if /api/accounts/me returns proper response redirect to dashboard, same as now, but in case of 404 redirect to registration view
• [x] Registration view should now only be accessible to logged in users
• [x] First section of registration form (user info) needs to be dropped
• [ ] Redirect from registration to Microsoft login page

[kenzo23312]

@maciej-jaworski url to login /login/:token