Fix showing the project's display name
Fix a "Argument isn't numeric" warning if there are not jobsets
Allow only project owners to delete projects / jobsets

Giant gaping security hole.
Revert "Add a dependency_lookup configuration option to enable (slow) dependency lookup in queue. This behaviour was disabled temporarily in accefbb79 due to slowness in very large queues, but some people might be dependent on it, so it is configurable until the previous behaviour is implemented more efficiently."

This reverts commit 24f5a6b15ff148ac339918a998aa1291ad2c933f.
Restore old findBuildDependencyInQueue behaviour