Add monotrail-utils crate

[cnpryer]

UPDATED:

This PR moves RequirementsTxt to a new monotrail-utils crate.

Summary of changes:

1. Add monotrail-utils crate
2. Move RequirementsTxt over
3. Use RequirementsTxt in poetry_integration

Tag https://github.com/mitsuhiko/rye/pull/265 Closes #56

[konstin]

Move the poetry integration usage into monotrail-utils

Could you use the monotrail_util RequirementsTxt in the poetry integration?

We also need updated CI workflows to publish monotrail-utils to crates.io, not necessarily now but before it blocks downstream crates from publishing to crates.io

[cnpryer]

Could you use the monotrail_util RequirementsTxt in the poetry integration?

I'll check it out.

[cnpryer]

I can look into making a PR for the CI after if that's alright with you.

I'm planning on getting https://github.com/mitsuhiko/rye/pull/265 ready for a review next. Then I can loop around to the CI.

[cnpryer]

I have the same 12 pass 1 failure (wheel::test::installed_paths_relative) on main for cargo test --workspace. I'll look again later.

UPDATE: #56

[cnpryer]

I can create an issue for this, but on main cargo test --release results with

failures:
    test_flipstring
    test_pipx_black_version
    test_poetry_config
    test_srcery

I'm on macos.

UPDATE: https://github.com/konstin/poc-monotrail/issues/55

[konstin]

Thanks!