Persist errors and status for reconciliation runs

[chadlwilson]

Context / Goal

In #12 we persisted the results of successful runs. Additionally, errors are returned via the API, however they are not persisted, so if you retrieve the run later it will just look like it is pending.

Expected Outcome

• Introduce a way to persist some kind of status of a rec Run, and some details of the failure (if it occurs)
• This should be retrievable via the API if Ability to extract/query for reconcilation report results #13 is implemented

Out of Scope

Additional context / implementation notes

[chadlwilson]

Done

• Status persisted and returned via API (Pending|Successful|Failed)
• Runs now return a failureCause via the synchronous trigger API rather than a generic 500 error JSON

Still to do

• Return 4xx error for source|target DB failures on API rather than HTTP 200?
• Persist the failureCause messages or structure to the DB so they can be retrieved historically