Install mime.types and magic in conf/ if they don't already exist.

This also re-enables existing logic to always install *-std.conf with
substitutions made.  These are then copied into *.conf (without the -std) if
that file doesn't already exist.

style police: please chill for a bit.  I intentionally didn't re-format
the indenting in this commit to make it easier to review.


git-svn-id: https://svn.apache.org/repos/asf/httpd/httpd/trunk@96127 13f79535-47bb-0310-9956-ffa450edef68