DA Layer Submission Failures should result in incremental backoff

[jbowen93]

Currently DA Layer submissions are retried immediately. This means that all 10 attempts may occur during a single transient delay. We should configure the retries to use an incremental backoff.

https://github.com/cenkalti/backoff

Example Error Log

9:39PM ERR DA layer submission failed error="Post \"http://127.0.0.1:26658/submit_pfd\": context deadline exceeded (Client.Timeout exceeded while awaiting headers)" attempt=1 module=BlockManager
9:39PM ERR DA layer submission failed error= attempt=2 module=BlockManager
9:39PM ERR DA layer submission failed error= attempt=3 module=BlockManager
9:39PM ERR DA layer submission failed error= attempt=4 module=BlockManager
9:39PM ERR DA layer submission failed error= attempt=5 module=BlockManager
9:39PM ERR DA layer submission failed error= attempt=6 module=BlockManager
9:39PM ERR DA layer submission failed error= attempt=7 module=BlockManager
9:39PM ERR DA layer submission failed error= attempt=8 module=BlockManager
9:39PM ERR DA layer submission failed error= attempt=9 module=BlockManager
9:39PM ERR DA layer submission failed error= attempt=10 module=BlockManager
panic: Failed to submit block to DA layer!