Automate setup for wicketd/wicket manual testing flow

[sunshowers]

PR #5551 adds some commands to the wicket README to manually set up sp-sim, MGS and wicketd. To my knowledge there isn't an automated way to run all of these commands together (we have tests that do this, but nothing automated) -- it would be nice to have one.

[jgallagher]

omicron-dev mgs-run will start sp-sim and MGS. Maybe that could grow a wicketd-run that would start them plus wicketd?

[sunshowers]

Oh neat, I didn't know about omicron-dev mgs-run. That's really helpful!

[sunshowers]

Hmmm, but also omicron-dev mgs-run takes a while to build because it compiles in a copy of Nexus.

[sunshowers]

I'll work on this after r8. I'll make omicron-dev itself a wrapper binary that compiles and execs a process with the right set of features enabled -- this should enable a quicker iteration cycle when Nexus is not part of the feature set.

[sunshowers]

#5551 adds notes to the readme. We'll want to update this once omicron-dev becomes smarter.