Exponential with jitter backoff

[JimNero009]

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Description of change

Add a new backoff class for a simple exponential backoff with jitter.

[petyaslavova]

Hi @JimNero009, thank you for your contribution! We’ll review your change soon.

[petyaslavova]

Hi @JimNero009, can you please add unit tests to your change?

[JimNero009]

@petyaslavova sure! I've added something that makes some sense now, how's that?