Add basic legacy login

Add initial setup/context and first login feature to login to administration interface
I do understand the idea of changing the landing page, that also needs to be tested but also needs to be a different feature, which will have different given parameters.

Here, since there is nothing changing it, we assume that the installation is a default one.

For the different landing page it should be something like:
```
Scenario: Change default landing page
    Given there is a Content object "New Page" of Content Type "landing page"
    And after login the default landing page is "New Page"
    When I log in as an administrator user
    Then I see "New Page" page
```