Build up the config lines we generate for the <VirtualHost> container
in a list, and then insert that list line by line, instead of having
lots of <% ... %> and <%= ... %> sections.  I think this way may be a
bit easier to read when the ERB template gets more complicated.

We actually had a section of outcommented code that tried to do this.
That outcommented section had been in the file since I committed it
originally back in 2014.  I probably intended to remove it before I
checked in the file, but forgot to do so.  But that snippet prompted
me to do this refactor now...