scx_bpfland: convert scheduler crate into lib+bin crate

[vnepogodin]

This PR converts scheduler scx_bpfland crate into lib+bin crate, to be able to use(load/unload) scheduler by other crates

[arighi]

I really like the idea of providing the Rust schedulers both as binaries and libraries! This can facilitate the development of tools / managers / meta-schedulers, simply by importing them as "libraries".

I'm not sure if it's better to create separate PRs or make a single PR. Also this may impact the workflow and potentially pending changes that people may have. We should discuss this during office hours to make sure everyone is aware (and agree with this) to better coordinate this change.

[vnepogodin]

I'm not sure if it's better to create separate PRs or make a single PR. Also this may impact the workflow and potentially pending changes that people may have. We should discuss this during office hours to make sure everyone is aware (and agree with this) to better coordinate this change.

yeah I agree with that

[arighi]

I'm going to close this one for now. I think the plan is to have scx_loader running the scheduler binaries first, then at some point in the future we may decide to resume thiis lib/bin approach. Feel free to re-open it if needed.