Add support for ostree-based Linux distributions

[Hofer-Julian]

Fixes #389
I've tested this planner on Fedora Silverblue and Endless OS.

The content is inspired by the linux planner, the steamos planner and https://github.com/dnkmmr69420/nix-installer-scripts/blob/main/installer-scripts/silverblue-nix-installer.sh

Description

Checklist

• Formatted with cargo fmt
• Built with nix build
• Ran flake checks with nix flake check
• Added or updated relevant tests (leave unchecked if not applicable)
• Added or updated relevant documentation (leave unchecked if not applicable)
• Linked to related issues (leave unchecked if not applicable)

Validating with install.determinate.systems

If a maintainer has added the upload to s3 label to this PR, it will become available for installation via install.determinate.systems:

curl --proto '=https' --tlsv1.2 -sSf -L https://install.determinate.systems/nix/pr/$PR_NUMBER | sh -s -- install

[Hoverbear]

Thanks for this! I'll need to do some testing. :)

(Don't worry about the CI failures here -- We need to rework our CI to better handle contributor PRs apparently...)

[Hoverbear]

It's a real bummer I can't seem to find any official silverblue vagrant boxes to use in the VM tests.

[Hoverbear]

I wonder if we should make ShellProfileLocations::default() check if the items if candidate paths are read-only and exclude them...

[Hofer-Julian]

I played a bit with this, but couldn't find a good way to do this.
One alternative would be to stop erroring when this files cannot be created and logging warnings instead.

[Hoverbear]

Let's punt it for now. :)

[Hofer-Julian]

Not sure what that means 😅

[Hoverbear]

I found a few very minor tidy-ups and nits to address, otherwise this seems to work really well! Thanks so much!

• Installed in a vm
• Services have no errors
• Ran some nix commands (nix run nixpkgs#hello, nix store gc etc)
• Rebooted
• Ran some more nix commands (nix run nixpkgs#hello, nix store gc etc)
• Uninstalled
• Installed again
• Ran some nix commands (nix run nixpkgs#hello, nix store gc etc)
• Ran sudo rpm-ostree install ripgrep
• Rebooted (as suggested)
• Ran some nix commands (nix run nixpkgs#hello, nix store gc etc)

I'd like to spend a bit of time learning more about ostree and seeing if we can use systemd-tmpfiles instead of the chattr dance before merging, too. -- After some poking I don't think it's going to work any better than chattr unless there is some way to do this with tmpfiles I haven't found.

[Hoverbear]

Thanks for this!