Update Vagrant Icinga 2 test config

refs #6127
Fix problems with the Puppet manifest when PostgreSQL's default encoding isn't UTF-8

fixes #6211
Multistep pages should have the possibility to add additional submit btns

refs #6136
Multistep page names should not be set implicitly on instantiation

refs #6136
Add placeholders for our wizard pages

refs #6136
Fix that Form::reset() does not clear sub forms as well
Multistep page configurations need not to be writable

refs #6136
Add wizard step to show and check requirements

resolves #6139
Add token authentication to the installation wizard

resolves #6135
Add form elements and validation for AdministratorForm

refs #6134
Move form options to external properties

refs #6134
Add form as Page to InstallationController

refs #6134
Fetch users from backends and populate multi-option with usernames

refs #6134
Adjust administration page to suit the updated requirements

refs #6134