Implement RawPOSIX command line tool set

[Yaxuan-w]

Description

RawPOSIX should have identical behaviors with native linux in syscall level, which make things like delete non-empty dir inside rmdir() shouldn’t be handled in RawPOSIX because native linux also doesn’t support. But we need to provide a way that users can mange RawPOSIX file system without accessing the file system root.

Potential Solution

I think we can implement sth like a command line tool set to allow users manage rawposix-fs through command line, and that would be pretty straightforward because we only need shell scripts to add RAWPOSIX_ROOT to user command (ie: cp/rm etc)