Improve reporting of errors when resolution is impossible

[TG1999]

resolvelib.resolvers.ResolutionImpossible: [RequirementInformation(requirement=<Requirement('boolean.py==4.0')>, parent=None), RequirementInformation(requirement=<Requirement('boolean.py>=3.5')>, parent=Candidate(name='aboutcode-toolkit', version=<Version('7.0.2')>, extras=set())), RequirementInformation(requirement=<Requirement('boolean.py>=3.5')>, parent=Candidate(name='aboutcode-toolkit', version=<Version('7.0.2')>, extras=set())), RequirementInformation(requirement=<Requirement('boolean.py==3.8')>, parent=Candidate(name='aboutcode-toolkit', version=<Version('7.0.2')>, extras=set())), RequirementInformation(requirement=<Requirement('boolean.py==4.0')>, parent=None), RequirementInformation(requirement=<Requirement('boolean.py>=3.5')>, parent=Candidate(name='aboutcode-toolkit', version=<Version('7.0.2')>, extras=set())), RequirementInformation(requirement=<Requirement('boolean.py>=3.5')>, parent=Candidate(name='aboutcode-toolkit', version=<Version('7.0.2')>, extras=set())), RequirementInformation(requirement=<Requirement('boolean.py==3.8')>, parent=Candidate(name='aboutcode-toolkit', version=<Version('7.0.2')>, extras=set()))]

This is not super user friendly, we should be able to infer why the resolution is impossible.