Now we need to install XRootD with SSI from our own respository

This needs to be reviewed but for the time being there should not be a
short timeout.

The appearance and disappearance of the agents is totally asynchronous for the garbage collector.
For this reason, GC should tolerate deletion of object at any time. This commit fixes the case where the
object disappears shortly after the garbage collector decides to watch it.

ls' command. Fix spaces in outputs.

Purging Oracle DB recycle bin in init, otherwise CI DB size explodes because of the recycle bin content.

The locks in Rados have timeouts. They are needed in case a locker process dies without
releasing its lock. As we have some contention in heavily loaded situations, it can happen
that a process is till accessing objects while the lock is expired. To lessen the likeliness
of this situation, the timeout has been increased from 10s to 60s.

The backoff was ajusted using the MultithreadLockingInterface unit test, with printouts
allowing to visually see the effect of the backoff strategy. The printouts are committed,
but they are commented out.

The same unit test was fized as it used to create an empty object, which is not supported
anymore in order to be able to detect locking of non-existing objects (lock creates the object,
but we detect non-existence as it is empty and re-delete it.

This mechanism of empty object locking detection is also added to the async update of object
as it was missing there (and the backoff has been added there too).

Added unlocking a non-scoped lock if needed.
Added more information in logs.

Name of object was already present in some errors but not all.

DriveState.

- when failing to schedule.
- now list which drive has an existing mount (at schedule time as well.

XrdSsi headers will be merged into master branch, but move into private/

It was wrongly added to OStoreDB::ArchiveMount::getNextJob() instead in a05ad490.

Timeouting full runs after 50 minutes: 10 minutes for namespace creation and 40 minutes for the test, so that gitlab does not times it out and leaves a dirty CI runner.

Performing 100 rm in parallel for rados, this should not be painful as those synchronous rm are mostly waiting

Updates to XRootD SSI to fix bug with using SSI + OFS similtaneously

XRD_TIMEOUTRESOLUTION=600   # increased from 15s

replaced eosh script with ls -y except after retrieval as archived and
retrieved are the same status regarding eos...
Looks like sometime ls -y determined archived files is not a growing
function...

client_ar.sh can now write to /eos/ctaeos/preprod with -d option, just complains: Could not remove disk replica for /eos/ctaeos/preprod/ as drop is already done in the wfe script. Should test for disk replica before trying to drop with ls -y on directory.