* remove useless resource lock
Resource locks need to be before the background task. creating same publish endpoint at the same time is unlikely...
* load data inside background tasks
This fixes a flaw in async apis, which loaded the published repo from the DB and mutated it outside the task closure, before the task lock was acquired.
Perform collection.LoadComplete inside maybeRunTaskInBackground and have tasks use a fresh copy of taskCollectionFactory, taskCollection
* lock source repos/snapshots for publish operations
Concurrent tasks were not properly locking their resources, leading to inconsistent published indexes:
SourceLocalRepo: iterate published.Sources (component -> source UUID), look up each local repo via localRepoCollection.ByUUID and append string(repo.Key()) to resources
SourceSnapshot: iterate b.Snapshots,look up each snapshot via snapshotCollection.ByName and append string(snapshot.ResourceKey()) to resources.
* lock pool on non MultiDist publish
* revert mutex on LinkFromPool
* use uuids, since names can be renamed
André Roth