Part of https://github.com/ooni/probe/issues/2184, because I wanted
to allow swapping commands and options more freely.
As a side effect, this PR closes https://github.com/ooni/probe/issues/2248.
AFAICT, every usage that was legal before is still legal. What has
changed seems the freedom to swap commands and options and a much
better help that lists the available options.
I made a mistake while adapting code from an experimental branch thus
breaking these two experiments because of interface conversion.
This diff fixes it.
While there, remove the panic trap for miniooni. Because miniooni is
an experimental tool, we want to see the full panic text, which definitely
leads to a more pleasant and effective debugging experience.
See https://github.com/ooni/probe/issues/2216 for context on why we
were trying to change how we register experiments.
The broken commit is 6a0ae5c70b.
