**As** an OpenProject admin
**I want to** be able to configure SAML using a user interface
**so that** I don't have to use a command line and can see potential errors more easily.

Also: Due to the lack of a user interface it's currently impossible to configure SAML yourself unless you are self-hosting. In which case you have to do it by editing a yml file or using the rails console, both of which are not very user friendly ways of doing this.

**Acceptance criteria**

* a screen allowing the configuration of SAML under Administration -> Authentication Begin of the insertion

End of the insertion Begin of the deletion
End of the deletion * It should pre-fill new configurations with the most common options by default Begin of the insertion

End of the insertion Begin of the deletion
End of the deletion * Begin of the insertionallow pre-filling the options based on a given metadata URL

* End of the insertion it should allow custom options (perhaps as json or yaml) Begin of the insertion

End of the insertion Begin of the deletion
End of the deletion * it should show the most recent authentication attempts along with potential errors that occured during it (e.g. missing fields that have to be configured in the SAML server)