Improve ServiceBus connection error handling to avoid slow down

[simon-20]

Brief Description
When there is a problem connecting to the ServiceBus, errors are not handled well, and timeouts are high.

This means that the main checker loop can take about three times as long (if the IATI MQ is down or unavailable or full) for several hours.

Also, because the connection isn't cleaned up properly, the BDS can run out of file descriptors, because it doesn't free them up quickly enough on error.

Severity
High