The jobs will now remain attached to the agent of the drive process. The garbage collector
process will now requeue them instead of drive process. This will allow the drive process
to restart faster for a new session and the drive process to requeue the jobs faster a it
processes jobs in bulk.

Also cut the main garbage collection function into smaller bits.
We requeue jobs in batches of 500.

This will allow locating exceptions potentially leaking out of rados calls.

Fixed various bugs detected through it.

This reverts commit 5ac9086c.

The CI was incorrectly failing.  There was nothing wrong with
the original commit that made the Catalogue class a pure
interface.

This reverts commit e07bb359.

Added options, suppressions and re-implemented BackendVFS::AsyncLockfreeFetcher to try and make valgrind happy.

Added dump for ArchiveQueueShards.
Unit tests now pass with sharded archive queues.

Updated locking of ObjetOps in order to allow locking of sub-objects.
Make cta-objectstore-dump-object lockfree.

Reduced usage of RetrieveQueue::dumpJobs() in general.
Removed dead code.
Added locking checks where missing.

Reduced usage of ArchiveQueue::dumpJobs() in general.
Removed dead code.

We now copy instead.

Adapted garbage collection.

Adapted garbage collection.

In preparation to sharded queue where the add/pop and commit will be merged.

Adapted MemQueue<objectstore::ArchiveRequest, objectstore::ArchiveQueue>::specializedAddJobsToQueue()
to call the new function.

Also added an access after each context in order serialise their creations.
Logs should at least permit better understanding of crashes.

The rados operations now round-robin on the contexts to spread the load.
Modified the not yet used thread pool of BackendRados so it does not have its own context
anymore.

This reverts commit a3c278a5

Each thread has its own rados context. The thead pool, when used will allow better
parallelism of asynchronous requests.

This required some rework on the backend creations as the threads will need logging.

This ensures the uniqueness of the agent name even if a process creates an agent several times in the same second.

They prevented propoer statistics update.

Some typo fixes.