Support replacing composefs/composefs

[cgwalters]

Migrating this here from composefs/composefs#423 (reply in thread)

Acceptance criteria:

• Can replace the Debian and Fedora packages of composefs with this project
• Include all man pages, etc.

[travier]

From a side chat:

Goals

• Move away from the C implementation and replace it with the Rust one
• Can replace the Debian and Fedora packages of composefs with this project
• Include all man pages, etc.

Remaining work

Support for composefs v1 (C) format:

• Initial reimplementation of composefs-c #225
• Extend v1 EROFS to OCI and booting #297

C library from the Rust one:

• Cdylib: crates: add composefs-capi cdylib crate #321
• Testing, validation and review for this PR

Release a new version composefs-rs as 2.0.0 (higher version than C library)

• Move / copy over all the man pages

Packaging work Fedora & CS/RHEL

• Update specfile to install new Rust library, binaries, man pages

Alongside work

Stabilize the format: #324

• Declare it stable
• Add some CI to validate that

[cgwalters]

cc rpm-software-management/rpm#4223

[giuseppe]

is there anything more left to do for this task?

[cgwalters]

I think we need a new release, then we could try e.g. updating Fedora rawhide ? If that sticks I think we're done!

I have some lingering worries about our testing of the shared library actually working, also I don't think we've tested the mkcomposefs impl with the podman-composefs backend?

But other than that...yeah I think we're close!