Add style and view scripts for first prototype

refs #6136
Add multistep form

refs #6136
Redirect to /install when the setup.token exists but no config.ini

refs #6136
Make it possible to disable form submit buttons forcefully
Fix subForm functionality
Multistep pages should not have random generated names

refs #6136
Fix multistep form creation

refs #6136
Make it possible to recreate a form
Fix multistep page creation

refs #6136
Multistep pages should know about their multistep form

refs #6136
It is a multistep page's responsibility whether it is shown to the user

refs #6136
Merge branch 'feature/install-wizard-6136'

refs #6136