mod_substitute: Allow to configure the patterns merge order with the new

SubstituteInheritBefore on|off directive (with default in 2.2 of 'off)

Backports: r1684900, r1687539, r1687680, r1688331, r1688339, r1688340, r1688343,
           r1697013, r1697015
PR: 57641
Submitted by: 
     [Marc.Stern <Marc.Stern approach.be>, Yann Ylavic, William Rowe]



git-svn-id: https://svn.apache.org/repos/asf/httpd/httpd/branches/2.2.x@1750835 13f79535-47bb-0310-9956-ffa450edef68