feat: add 'fromager resolve package' subcommand

[tiran]

The new resole package subcommand is designed to debug Fromager settings and resolver properties. It compares the results from Fromager's internal resolver with a simple PyPI lookup. It prints informations like resolver configuration, detected versions and versions with sdists and wheels on PyPI.

$ fromager --debug resolve package 'fromager~=0.68.0'
15:28:52 INFO loading settings from .../overrides/settings.yaml
15:28:52 INFO fromager: resolving requirement for 'fromager~=0.68.0'
15:28:52 INFO fromager: sdist server url: https://pypi.org/simple/
15:28:52 INFO fromager: resolver includes sdists: True
15:28:52 INFO fromager: resolver includes wheels: False
15:28:52 INFO fromager: download url: None
15:28:52 INFO fromager: get_resolver_provider returns 'PyPIProvider'
15:28:52 INFO fromager: found 2 Fromager candidates with 2 unique versions
15:28:52 INFO fromager: Fromager versions: 0.68.0, 0.68.1
15:28:52 INFO fromager: found 2 versions on PyPI
15:28:52 INFO fromager: PyPI versions: 0.68.0, 0.68.1
15:28:52 INFO fromager: - with sdists: 0.68.0, 0.68.1
15:28:52 INFO fromager: - with wheels: 0.68.0, 0.68.1

[tiran]

I'm marking this as a draft, because I have not added documentation and tests for the new code.

[rd4398]

I maybe wrong, but can we name the command as fromager debug resolver?

fromager resolve package is sounding like we are running fromager's bootstrap command under the hood

[dhellmann]

It would be good to align the UX of this command and list-versions. That one has CLI switches to control the type of package allowed, for example, which could be useful here for testing if configuration changes help with a problem.

We should also work out some naming conventions. As we get more commands, they aren't as nicely organized as they could be. I like systems that use "noun verb" because if I know the noun then tab completion can help me find the verbs. So in this case we might have "package resolve" for this command and "package list-versions" for the other.

Perhaps the 2 commands should be merged with "list-versions" becoming a --all flag on "package resolve"?

None of these comments should block this from merging, but it would be good to work out a plan and clean things up afterwards.