Underline text in DT tags. Refs #2627

The underline style is no more applied automatically.
Changed default ValidFrom to "any network". Refs #2548

New value is "0.0.0.0/0.0.0.0". A TODO remainder for the admin should be added to fix this.
Don't stop httpd-admin on shutdown runlevels. Refs #2629

This change gives enough time for server-manager to return a response
to the client.