When adding menu links, check for links to the homepage, and don't add them

Problem/Motivation

Some menus will include links back to the homepage, especially menus besides the main menu. These create scenarios that are a duplicate of the homepage link.

Steps to reproduce

- Create a new menu, and add a link to the home page.
- Include the new menu in a profile
- Include the homepage checkbox
- Generate the backstop file
- An additional scenario is created for the menu homepage link

Proposed resolution

Check the menu links, and remove any that point back to the site root