Review need for auto-retries

[conorbarford-ping]

Following from #494 with auto-retries optional and customisable, ideally shouldn't be needed at all, with either frodo or the product being consistent.

This ticket is for the long-term tracking of intermittent and unpredictable errors and what can be done with them.

[pmckeown]

I've seen this issue too. Sometimes script pushes fail but frodo doesn't exit. It does exit though when the journey that relies on the script is not present.