clean up cmd_parms: config_file is no longer valid; end_token is bogus;

clean up cmd_parms: config_file is no longer valid; end_token is bogus;
    add directive.
move configfile_t and functions from httpd.h to http_config.h
new signature for ap_build_config() (since config_file removed from cmd_parms)
add "data" to ap_directive_t for future use by modules. add filename.
syntax checking for section-close directives: a section-open must exist,
    the section-close must be </FOO>, and the open/close must match.
    the file as a whole must be properly balanced (issue errors for each
    unmatched section-open).
</FOO> command_rec structures are obsolete. Remove from http_core.c.
do not store </FOO> directives in the config tree.
clean out section-close logic from http_core.c (and old, related comments)
<Limit> and <LimitExcept> must walk their children.
new mechanism in ap_check_cmd_context() for testing enclosure in a
    Directory/Location/File: find_parent()
<IfModule> and <IfDefine> must pass cmd->context when walking the children
several places: we had a walk followed by ap_get_module_config(). that
    assumed the walk would create a config that we could fetch, which is not
    true -- it is possible that the children are all from other modules
    (e.g. the <Files> section in httpd.conf-dist has no "core" directives).
    using ap_set_config_vectors() ensures we get a structure, and it returns
    it to us.
    [ note: when we had </Directory> (and friends) in the tree, the config
      would get created; removing the directive removed the config; this
      was a bitch to track down :-) ]

git-svn-id: https://svn.apache.org/repos/asf/httpd/httpd/trunk@85024 13f79535-47bb-0310-9956-ffa450edef68