The first edition that can load and execute single program

[imlk0]

This PR handles the loading of the program and the translation of a small part of the syscall:

• Implement execve::exit::transfert_load_script()
• (Simply) Implement open::enter(), standard_syscall::enter(), and open_at::enter()
• Some bug fixes
• Signal delivery

Note that currently it can only be compiled and run on x86_64 Linux, and contains some unresolved issues.

You can test /bin/sleep it should execute correctly:

# build proot-rs
cargo build
# run from binary
./target/debug/proot-rs --rootfs=./rootfs /bin/sleep 3
# or run with log level set to `trace`
RUST_LOG=trace ./target/debug/proot-rs --rootfs=./rootfs /bin/sleep 3

The expected behavior is that it will wait three seconds and exit with zero code