Refactor transitions functions for testing

[aclavio]

A "save" parameter was added to enable unit testing of the various transition functions:

• executeStateByJobDoc
• startProcessingFlowByJobDoc
• retryJobAtStateByJobDoc
• resumeWaitingJobByJobDoc
• transition

These functions should be refactored to remove all document updates, and only mutate and return the job object in memory. Corresponding functions should be added which calls these functions, and save the result (resume and retry already partially implement this). The "save" parameter can then be removed.

This will allow the unit tests to simply call the mutator functions without the "save" parameter, and the application code to call the function which commits mutated job document.