The `subpageof` keyword allows you to find subpages of a specified page, e.g. archived user pages.
We want to support this functionality through the advancedSearch form
The field should be located as shown in the mock, with the label as shown in the mock
**Info i text**
 The field and label are located as decribed
 The whole field is for one page name, no pills are created
 When entering a page name into that field, subpages are shown in the result list
 The info i is layouted equally to all existing info texts on advancedSearch, and the contents is what is described above