TurnitinOC - retry delay algorithm improvements

A couple constants are defined:

private static final int TURNITIN_OC_MAX_RETRY_MINUTES = 240; // 4 hours
private static final int TURNITIN_MAX_RETRY = 16;

Following through the retry delay algorithm:
Σ(retry = 1..16) min(2^retry, 240)
2+4+8+16+32+64+128+240*9=2414 minutes
The delays sum to ~40 hours

In our experience there are situations where Turnitin servers are unresponsive, or a change is required on our side, and the retry automatically corrects it. But in many cases it takes more than 40 hours before these situations are resolved.

Also, there are a couple success scenarios that apply the retry delay. I have to investigate further, but I suspect that if one of these delays follows after errors occur earlier in the process, items may be needlessly stuck for 4 hours. I'm not positive if this seriously warrants a fix, but it's very beneficial for testing, as these 2 minute waits add up (I've been updating the contentreview_item table, setting nextretrytime=now() on the rows of interest)

Add configuration to modify the behaviour of how we delay between retries