Changed reporting to the Catalog with a batch of written files.
Changed synchronous reporting to the backend job by job to the
asynchronous reporting for batch of jobs.
Changed synchronous reporting to the EOS mgm to the asynchronous
reporting.

Update the protobuf file to the version required by EOS-CTA SSI
interface and delete all source code that depends on the previous
version (i.e. all the opaque query code).

The framework does not throw exceptions to the client, instead it puts
the exception in an Alert and calls the AlertCallback to log it.

* EOS->CTA is a Notification message
* CTA->EOS is a Response message (sent as Metadata)
* Optional Alert for extra log messages (sent as Alert)

A top-level string which is unassigned will be assigned a default value of empty
string. If we put it inside a nested message, then an unassigned string has no
value.

No wrapper for sent messages (as only one message type can be sent). Defines a
wrapper for received messages. Defines message types for errors and alerts.

Changes to protobuf breaks cta-xrootd_plugins-write-notification-msg, so
I removed it from the build in this branch.

The report of a file being archived will now timeout after
15 seconds when trying to connect to EOS.   The previous
timeout was 8 minutes.

The 8 minute timeout was so long that the "kill a stalled
data transfer session" logic would kick in before the
timeout expired.  This killing logic would then mask
the underlying problem.