Error when adding a new page in a Space without Home page should be handled more gracefully. Currently it throws a System Error.

The system should display a warning informing the user that to be able to add a page, the space must have a Home page, because all pages created in a Space takes the Home page as their parent.

Steps to reproduce:

1. Create a Space.
2. Remove its Home page (as per image below):

3. Try to add a new page:

4. The system throws an error:

Workaround:

1. Create/Open another Space
2. Copy its Home page
3. Move the copy to the homeless Space