Support nested archives

[moi90]

Currently, it is impossible to access nested archives:

from pathlib import Path
import zipfile
from archive_path.zip_path import ZipPath


def test_archive_path(tmp_path: Path):

    archive_dir = tmp_path / "path/to"
    archive_dir.mkdir(parents=True)

    archive_path = archive_dir / "archive.zip"

    with zipfile.ZipFile(archive_path, "w") as zf1:
        with zf1.open("nested.zip", "w") as f:
            with zipfile.ZipFile(f, "w") as zf2:
                zf2.writestr("hello.txt", "Hello World!")

    print()

    with ZipPath(archive_path) as zp1:
        with ZipPath(zp1 / "nested.zip") as zp2:
            # Should be path/to/archive.zip/nested.zip
            print("zp2:", repr(zp2))

            # Fails: FileNotFoundError
            zp2.read_text("hello.txt")

zp2 is ZipPath('.../path/to/archive.zip', '').
This is because of reuse of a parent archive in the constructor.

Instead, I suggest to use a private parameter to ZipPath.__init__ to pass along a shared _zipfile, so that we do not need path for that. Furthermore, ZipFileExtra should use Path.open instead of io.open so that path instances of any kind (e.g. ZipPath) can be used.

[moi90]

Context: I'm working on a universal Path implementation that allows me to work on paths like "/path/to/archive.zip/nested.zip/hello.txt" transparently.