Lock down the source parameter to real system codes

[rowanmanning]

The source parameter should be checked against a list of valid system codes using @financial-times/source-param-middleware. This will require a v3 release as it's a breaking change.

[chee]

@Financial-Times/origami-core hello, Origami Core.
It looks like Financial-Times/source-param-middleware is now archived.

What should we do about this, and with this issue?

[chee]

https://github.com/Financial-Times/biz-ops-client

[chee]

https://github.com/Financial-Times/origami-build-service/blob/66af1d9911a1d0acd03ce2ed4e51c3435ef43293/lib/middleware/v3/parseSystemCodeParameter.js#L42-L64

[JakeChampion]

We could add that code in a log-only mode to track how many are not valid system codes - then we would know which products would need to update their source parameter value