LPS-44575 Include private layouts into login process
LPS-44575 Search for /login page also in the private site
LPS-44575 Login request is also request targeting Sign in portlet on /login page
LPS-44575 Allow displaying /login page from private site, but only when it has Sign in portlet to avoid unwanted exposure of private layout
LPS-44575 Allow Guest role to display the Sign in portlet on the private page. Guest role has no permissions on private sites and is excluded from permission assignments UI