Remove out-of-date details about which modules are enabled by default

Remove out-of-date details about which modules are enabled by default
from the documentation, in favor of suggesting getting the up-to-date
information by running ./configure -h.

The special cases previously documented here (such as, this module
depends on this other module, or you probably don't want this module
unless you're a developer), have had that information added to the
output of configure -h in r1029814.

git-svn-id: https://svn.apache.org/repos/asf/httpd/httpd/trunk@1033032 13f79535-47bb-0310-9956-ffa450edef68