Backport:

 Some serious updates to the top section of the mod_dav docs.  Many of the ideas
  are stolen from Greg's mod_dav site.  Some specifics:

  - Change recommendations about where to place the dav lockfile and be specific
  about required permissions.

  - Remove the HEAD from the <Limit> block, since it is implied by GET.

  - Add a security section discussing file permissions, auth issues, denial of
  service, etc.

  - Add a "complex config" section discussing the dynamic content issue.

  Review requested.  Unfortunately, I can't check in the html because of
  transformation problems in my setup.


git-svn-id: https://svn.apache.org/repos/asf/httpd/httpd/branches/APACHE_2_0_BRANCH@99470 13f79535-47bb-0310-9956-ffa450edef68