Add "Test Data" that srepd can use for development

[iamkirkbater]

There should be a folder of test data structs that SREPD can use for local development.

When this local dataset is used for testing SREPD should not make any calls to PagerDuty, but should log what it would have done.

This would be useful for UI testing or other non-PD based testing, where you may not want to have to query actual alerts.

Specifically, I'm trying to test something but there's no alerts on the board, which is fortunate for Primary but unfortunate for me trying to test something.