* Basic onboarding modal that's shown to users once
* Lay out pages 2 through 5, add images, style modals (#1509)
* Lay out pages 2 through 5
Added images and laid out pages 2 through 5 in the jsx file. SCSS will
come, still working on just seeing if this works at all.
* Fix jsx errors, add images to modal pages, style modal pages
* Add animations to onboarding pager changes, improve wording and styling
* Finishing touches on the onboarding
* Add missing propTypes
* Update wording
An attempt to open a brand new Mastodon instance configured
as SINGLE_USER_MODE=true will cause an exception.
Enable temporary registration if we have no users in the database
Fixes#1817
Eugen