Implement improved compat sorting when multiple artifacts are compatible

[filiptibell]

This PR implements a secondary artifact sorting algorithm, that applies when all other sorting for OS and architecture compatibility are equal. Notably, installing selene, which has several tool artifacts in each release, will now work properly because the additional sorting algorithm allows us to accept more than a single compatible artifact per release, and choose the best.

System compatibility (OS, arch) still takes precedence over all other sorting and as such current compatibility with already working tools will not be affected.

Fixes #41

[Dekkonot]

When installing Selene, I still get a warning that says:

Failed to find a fully compatible artifact for kampfkarren/selene!
This seems to have been caused by selene not specifying an architecture in any of its artifacts.

I feel as though this is not what we should say when searching for a fallback (and in fact that process should probably be invisible to users outside of a quick message about what artifact is being used).

[filiptibell]

I feel as though this is not what we should say when searching for a fallback (and in fact that process should probably be invisible to users outside of a quick message about what artifact is being used)

That makes sense to me - I'll improve on this and tracing in general in another PR after this one 👍