Remove dependency on Pkg

[asinghvi17]

In Julia v1.11, Pkg is no longer part of the system image, and will introduce quite a bit of loading latency when the package is first loaded.

This PR removes the dependency on Pkg (it looks like only one Pkg function was used here).

[asinghvi17]

There is one thing left to remove here, which is Pkg.Operations.read_project. This is actually a big one, but depends on the nature of how this package is used.

Does anyone get the compat, weakdeps, etc sections from the project using the package, or is the only user-facing API the macros (which are accessing top-level fields)? If the latter, then removing Pkg becomes trivial. If the former, then we have to think about the return type.

[KlausC]

@asinghvi17 thanks for the suggestion to remove dependency on Pkg.
You see, that your changes do not compile yet, but that should be repairable:
Hints:

• Replace projectfile_path by Base.env_project_file (no need to copy from source from Pkg)
• add dependency from TOML
• replace 'Pkg....read_projectbyTOML.parsefile`
• replace Pkg.Types.Project by the Dict returned from parsefile

[KlausC]

ps: please test locally before publishing you changes

[asinghvi17]

That's why it's still a draft PR :D - I will probably update this with the rest of the fixes tomorrow.