feat(admin/notifications): add post setup notification
impr(admin/users): usability improvements

- add confirm dialog to user delete action
- code cleanup
fix(webapps/notificationsPanel): fix panels not being removed
impr(notifications): update position and naming

- notifications are now positioned in the top right corner of the screen
- update naming of notifications

Closes CAM-1055
Merge branch 'master' of github.com:camunda/camunda-bpm-platform