Use back-off strategy for log availability check

In DBZ-3635 we introduced a maximum number of retries variable in the Oracle connector to allow the connector to check up to a maximum of 5 seconds with a poll interval of 1 second. Unfortunately, this is still too rigid for some environments.

To enable full control of this the following changes are needed:

1. Make the maximum retry configurable via an internal property
2. Expose initial/max delay as configurable via internal properties for the back-off strategy