Retry vitess connection refused errors 100 times

[Pasakinskas]

Debezium embedded engine got connection refused from vtgate and started a crashback loop for uk portal. We've decided to limit the number of retries for this specific error. I've limited to a 100, because we have seen errors of up to 25 cases in a quick succession, probably due to network issues.

made the connectionRefusedRestarts atomic because VitessErrorHandler is marked as volatile in VitessConnectorTask

VStream streaming for keyspace:cstool_main and tables: cstool_main.levels  onError. Status: Status{code=UNAVAILABLE, description=io exception, cause=com.ververica.cdc.connectors.vitess.shaded.io.netty.channel.AbstractChannel$AnnotatedConnectException: Connection refused: vtgate-dwh-cstool.vtgate-dwh.svc.prod3.k8s.vinted.com/10.125.153.62:15991
Caused by: java.net.ConnectException: Connection refused
	at java.base/sun.nio.ch.SocketChannelImpl.checkConnect(Native Method)
	at java.base/sun.nio.ch.SocketChannelImpl.finishConnect(Unknown Source)
	...
}