Allow user modification of access and error log in vhost.

Motivation for this is some vhosts I didn't want to log anything.  The way I did it feels clunky to me but I try to favor cleaner templates over manifests.  Was going to add similar to logic to server logs for completeness. First wanted to check that this is alright vs doing something where logic is part template and part manifest (ie keep the assembled default log in template and use if blocks around it.