Explicitly set the 'vendor' flag on Foreman templates to 'Foreman'

This is another thing for downstream, we want to remove all Kickstart templates except the official defaults, but the problem is Foreman names are really generic.

If seeds is run a second time, and in between a user has created a kickstart called "Kickstart default", we'll end up deleting it and they won't be happy.

There's no change to Foreman users by setting this field.