Cleanup abbreviation

We have been using redirector's Organisation abbreviations in the app. This is not ideal as they were lowercase,  inconsistent with the official abbreviations and introduced an unnecessary dependency. Now we have the Whitehall API to get the official abbreviations from.

Additionally, in the near future, not all organisations will have passed through redirector, so we need to be able to cope without it.

The redirector import code legitimately still needs this data, so it remains there. It is also used in the Google Analytics ingestion code, but I can't see a cli-user-friendly alternative for that use case.

I sense this change may distress @rgarner...