Conflicts:
	xroot_ssi_pb/XrdSsiPbService.hpp

This led to garbage collactor segfaults.

This allows previously developped asyncLockfreeFetch to apply to it.

The previous strategy was made under the assumption that we needed to lock sparingly.
With the introduction of lockfree strategy, this is not true anymore.
The new strategy will be immune from the A watches B, B watches A, both die, and
no one garbage collects them situation (also called cyclers in utility cta-objectstore-unfollow-agent).

This will remove contention on the drive register as drives uipdate their statuses.
Also simplified structures in OStoreDB implementation (less references with added friend relations).

It was lowered during the watch based locking attempt.

This will allow indentification of impacted processes.

The missing unwatch fix should improve performance of watch/notify based locking significantly.
Instrumentation will log any call to rados longer that 1s to /var/tmp/cta-rados-slow-calls.log.
Also prepared a structure to allow switching between watch/notify and backoff based locking.
Backoff code is not yet brought back (will test with the unwatch fix first).

Added Castor_limits.man and source code of Csnprintf

Note that this change is a noop, as the code after compiler preprocessing does not change. This was actually double checked manually.

Note that this change is a noop, as the code after compiler preprocessing does not change. This was actually double checked manually.

In particular, dropped all code related to unsupported platforms.
Note that it has been verified that this commit is a noop for the compiled code as the preprocessed code is unchanged (modulo some line numbers).