Performance minded with some bug fixes

[matteius]

The issue

Testing against the sentry requirements file profiling from a fresh virtualenv creation with no Pipfile/Pipfile.lock: https://raw.githubusercontent.com/getsentry/sentry/refs/heads/master/requirements-base.txt

Main branch:

This branch:

The fix

• Reintroduce Pipfile caching -- carefully and with extra time checks
• Refactor resolver methods to reduce context managers
• cache the paths environment property.
• Solve edge case with markers not be passed through when installing from CLI
• Solve a different markers edge case
• Eliminate some dead (unused) methods

The checklist

• [ ] Associated issue
• [ ] A news fragment in the news/ directory to describe this fix with the extension .bugfix.rst, .feature.rst, .behavior.rst, .doc.rst. .vendor.rst. or .trivial.rst (this will appear in the release changelog). Use semantic line breaks and name the file after the issue number or the PR #.