Allow viewing of previous BM/GMM bodies when they share their abbreviation

[tomudding]

What would you like?

When bodies share the same abbreviation, provide additional routing like /association/{body}/{abbreviation}/{foundation_year} or /association/{body}/{abbreviation}/{decision_hash}.

Why is this needed?

An old body and a new body may share the same abbreviation. I fixed the underlying code to (again) properly support this through GH-982. However, this means that visiting /association/{body}/{abbreviation} only shows the last one.

Other information

No response

[tomudding]

Any abrogated body that is listed from the historical overviews should automatically use this route. On top of that, it should be possible to go to another "iteration" of the body from each "iteration" (maybe a dropdown?).