Add ability to use object handles as ACL source

[gentoo90]

This adds from_handle, from_file_handle, from_object_handle and from_registry_handle methods to ACL allowing to use Windows object handles instead of paths.

use std::fs::File;
use std::os::windows::io::AsRawHandle;
use winapi::ctypes::c_void;
use windows_acl::acl::ACL;

let file = File::open(path)?;
acl = ACL::from_file_handle(file.as_raw_handle() as *mut c_void, false)?;

CC gentoo90/winreg-rs#41

[CLAassistant]

All committers have signed the CLA.

[woodruffw]

Awesome, thank you! Would you mind adding some brief unit tests for these new API surfaces?

[gentoo90]

Would you mind adding some brief unit tests for these new API surfaces?

I'm not sure what is the best way to test this. Should I just copy the tests with from_file_path and replace it with from_file_handle?

[woodruffw]

I'm not sure what is the best way to test this. Should I just copy the tests with from_file_path and replace it with from_file_handle?

Yep, something like that sounds good to me.

[woodruffw]

Grr, CI got disabled at some point.

[woodruffw]

Thanks again!