Remove old logic in SolverOutputState.prepare_specs() and apply enabled cleanups

[jaimergp]

Description

In conda-libmamba-solver 23.9.0 we changed how we build the tasks for the libmambapy.Solver.add_jobs() method (#270). This allowed us to remove state.SolverOutputState.prepare_specs(), which tried to agnostically mimic classic's solver logic to add specs to pycosat, since we were not using it.

Since all the task state is now encoded in the tasks dictionary we iterate over before calling Solver.add_jobs(), we can also remove all the TrackedMap business (dictionaries whose operations had logged 'reasons'). Less code to maintain, less RAM used, everyone's happy.

Finally, since we have to iterate over some list of MatchSpec names, in some order (in #378 we have decided to do it alphabetically, but that's totally arbitrary), I took the opportunity to provide a SolverOutputState.specs property that iterates over all possible spec sources in a certain order that makes certain sense. Within each group, strictest specs go first (because we assume the user is putting extra effort in being explicit, so it must be important).

Spec order in each task is important for libsolv. Apparently first specs are considered earlier in the backtracking.

Checklist - did you ...

• Add a file to the news directory (using the template) for the next release's release notes?
• Add / update necessary tests?
• Add / update outdated documentation?

[jezdez]

Woah!

[jaimergp]

Whatever is going on with #317, this PR reproduces it reliably on Windows in the last few runs 🤷

[jezdez]

A few questions mostly, I may need a session of elaboration about this refactoring, my brain keeps not forgetting the start of the PR when I'm in the middle

[jezdez]

Just some minor questions and naming inconsistencies.

[jaimergp]

There's something off with test_install_update_deps_only_deps_flags. I need to look into it.

[jezdez]

Changed the base back to main, now that 23.12.x is out.

[jaimergp]

There's something off with test_install_update_deps_only_deps_flags. I need to look into it.

It fixed itself :D