MAINT Inject compat layer to Transaction

[ryanking13]

Related: #112

Another PR that removes direct ._compat import from child classes and functions. No functional changes are included.

[agriyakhetarpal]

Thanks, @ryanking13! The code changes LGTM. Could you please elaborate on the (immediate) further ideas after this PR? If I understand correctly, the idea in this PR has been to isolate the transactions better, based on the environment micropip is running in. I apologise that this PR has gone stale, in case your plans evade your memory!

[agriyakhetarpal]

I agree with the comment. Could you please open a issue to track it?

[ryanking13]

Thanks. I opened an issue to track the progress (#237). Not just for this comment but for overall refactoring for the compatibility layer.

[ryanking13]

Thanks for the question @agriyakhetarpal! The goal for these PRs is to remove the global compatibility layer and make it a dependency of the PackageManager class. By doing that,

1. Users can use their custom compatibility layer to modify the behavior of micropip. Ideally, it makes it possible using micropip in non-pyodide environment as well.
2. We can get rid of _compat_not_in_pyodide.py from the wheel. We can remove it or use it in test files only.

[agriyakhetarpal]

Thanks for the explanation! That makes sense to me.