Include pbs-sleep for linux distribution (renamed to pbs_sleep on all platforms)

Include pbs_sleep for all linux platforms. Including pbs_sleep in linux distribution for supporting container images that might not have a sleep binary. pbs_sleep will also be a single common sleep command for PTL tests on all platforms (including windows) for test jobs.

Please provide your valuable feedback.
Thank you.

looks good to me. Thanks!

I assume you mean using/enhancing the already existing pbs-sleep instead of writing a new binary pbs_sleep?

Enhancing the existing pbs-sleep for windows to support all linux platforms.

Thanks for clarifying. I would update the title and description to use a dash instead of underscore in order to avoid confusion.

Thanks @jnewman - have now updated the title to reflect exactly what we are doing.