Port `strace.py` to RepyV2

[Our Repy `strace` tool](https://github.com/SeattleTestbed/seattlelib_v2/blob/master/strace.py) doesn't use the up-to-date RepyV2 API. This should obviously be fixed.

([Wikipedia](https://en.wikipedia.org/wiki/Strace) or your Linux machine's manpages can tell you more about the tool our Repy thing was modelled after.)
