Use log saver instance id for checkpointing when more than one log saver instances are running
Use log saver instance id for checkpointing. Upon log saver restart, all the log events, that were not persisted before will be read from Log buffer and sent to log processor pipeline to persist them permanently. However, in order to figure out which instance wrote which checkpoint to checkpoint table, checkpoints should be stored per instance id.
This is needed when more than 1 log saver instances are running in k8s