`sdiff` command is not implemented

[oSoMoN]

Currently uutils' diffutils only implements the diff executable.

But GNU's diffutils also provide cmp, diff3 and sdiff.

This issue is a tracker for the implementation of the sdiff utility.

Documentation: https://www.gnu.org/software/diffutils/manual/html_node/Invoking-sdiff.html.

[sami-daniel]

taking this up