Add ++req option to suite commands

It would be a great convenience for suite commands to have a "++req" option to give the original request that generated the suite command, similar to the rez-context "--req" command.

Start by locating the suite command entry points and the existing rez-context "--req" option. Trace how the original request is available when a suite command runs, then add the corresponding "++req" behavior and verify that suite commands expose the request that generated them.

Written by the indexing model from the issue text.