Offer process termination

[mcandre]

Hi,

I am happy to report that process querying is working well with go-ps.

Could we add a portable Terminate() function to the process interface? This can help developers to cleanup after stuck processes in a platform independent way.

[mcandre]

I see that Go standard library's os package provides this functionality.

https://pkg.go.dev/os

Can we please add a Kill() method to the mitchellh Process interface, to match the capabilities of the standard library?