Add network worker for SNP

[CvvT]

This PR

1. Adds a background worker for network in SNP runner and fixes IPInterfaceProvider
2. Refactors the code to remove duplicate assembly code
3. Fix one more stack alignment issue

Most changes happen in sandbox_driver and snp-sandbox.

Now inside snp CVM, we can run

./sandbox_loader -n tun0 /out/tcp_server

[github-actions]

🤖 SemverChecks 🤖 ⚠️ Potential breaking API changes detected ⚠️

Click for details

--- failure function_missing: pub fn removed or renamed ---

Description:
A publicly-visible function cannot be imported by its prior path. A `pub use` may have been removed, or the function itself may have been renamed or removed entirely.
        ref: https://doc.rust-lang.org/cargo/reference/semver.html#item-remove
       impl: https://github.com/obi1kenobi/cargo-semver-checks/tree/v0.46.0/src/lints/function_missing.ron

Failed in:
  function litebox_platform_linux_kernel::host::snp::snp_impl::init_thread, previously in file /home/runner/work/litebox/litebox/target/semver-checks/git-main/24e54ec61cf39f72d29e245b0550ac25ed090e0e/litebox_platform_linux_kernel/src/host/snp/snp_impl.rs:207