new liveprop namespace registration and lookup. modules register each

    namespace they will use, which then receives a process-wide index.
get rid of old dav_liveprop_uris global (and minor cleaning in dav_dyn);
    encapsulate liveprop handling in liveprop.c.
do not build/use an ns_map; use dav_get_liveprop_ns_index().


git-svn-id: https://svn.apache.org/repos/asf/httpd/httpd/trunk@85800 13f79535-47bb-0310-9956-ffa450edef68