Add syndication out of sync healthcheck

[maxcbc]

Add syndication out of sync healthcheck

Problem Statement

When we receive a report that a contract or user is not getting the syndication layer. We need

• to be able to assertain where in the stack the issue has arisen, going all the way back to salesforce.
• to be able to be assured that our synchronisation is working

Solution

Part One

Add healthchecks for validating whether or not contracts and users are in sync with salesforce.

This could take the form of:

• A manual query of salesforce compared to postgres
• Noting failed contract syncs from the sqs queue

Part Two

Add run-book for the two new healthchecks. This may include:

• adding a remedial endpoint for ad-hoc manual targeted synchronisation from salesforce to postgres of a specific contract or user.
• adding a validation endpoint for ad-hoc manual checking of contracts in salesforce that should be copied over (i.e. just see their contract_id, dates of validity, date added).

[maxcbc]

@leggsimon