Pathauto settings check

Add in some checking for pathauto settings to see if they are optimal for SEO. For example, the "Update Action" has these options:

Create a new alias. Leave the existing alias functioning.
Create a new alias. Delete the old alias.

And neither of these are good for SEO. The first ends up creating 2 pages with the same content. The second one can cause 404 errors.

Since the default is the 2nd option above, it's important to add in some checking for these and provide some guidance as to better choices.