Rename the "daemon" directory to "xray"

[sprt]

When installing the daemon using go get, the binary gets installed in the $GOPATH/bin directory with the name daemon. A lot of Go users add that directory to their PATH, but daemon isn't a super descriptive command. I think it should be renamed to something like xray.

[yogiraj07]

Hi @sprt ,
Thank you for the feedback. In future, if we want to add new package to aws-xray-daemon path, the current daemon directory name helps in representing its functionality. Renaming directory to xray will limit the ability for future additions.

Best,
Yogi