[openFATE 305899] Build Service Package Locking

Feature changed by: Rémy Marquis (Spyhawk) Feature #305899, revision 3 - Title: Package Locking + Title: Build Service Package Locking Buildservice: Unconfirmed Priority Requester: Important Requested by: Will Stephenson (wstephenson) Description: * Lock a package * osc co -l checks out and locks * Anyone can unlock a package (to prevent deadlock) but it has to be explicit * https://build.opensuse.org/project/monitor to show locks and lock owners -- openSUSE Feature: https://features.opensuse.org/305899