[MRM-1702] make the locking configurable via the UI

git-svn-id: https://svn.apache.org/repos/asf/archiva/trunk@1550708 13f79535-47bb-0310-9956-ffa450edef68
mark locking as experimental

git-svn-id: https://svn.apache.org/repos/asf/archiva/trunk@1550709 13f79535-47bb-0310-9956-ffa450edef68