LG-504 Create a health checker for account reset notifications

[stevegsa]

Why: When a user requests an account reset we tell them their request will be processed in 24 hours. We have to be sure that the asyncronous processing of the grant notifications are occurring on a timely basis.

How: Add a health checker to the health_controller. Search for a single record in account_reset_requests where the request was not serviced in 26 hours (24 hours + a 2 hour buffer to service the requests). Return a bad health status if such a record is found. The table has an index that is optimized for this type of query while factoring in timestamps, cancellations, and requests already granted.

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[jgsmith-usds]

Style: this works just fine since we only do this once in a while. Another pattern I've seen is to select 1 so we aren't sending a lot of data over the network. We only care about existence.

[stevegsa]

Ah yes. I like!