Implement retries after database errors

[eliotjordan]

Summary or User Story

Currently, if a database error occurs during consumer write operations, the entire batch of records is missed. We need a way to detect errors and retry db commands.

Acceptance Criteria

• When there is an error connecting to the database, the command is retried until it succeeds. Evidenced by the test passing.

First step

Write test to demonstrate the problem.

[tpendragon]

Test is here: #284