We introduce the -f, --input-file FILE option with which we
are able to run an OONI Run v2 descriptor stored locally.
In this running mode, there are no checks related to whether the
descriptor has changed, since we're dealing with a local file.
Closes https://github.com/ooni/probe/issues/2328
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.
This diff splits miniooni's implementation in smaller and more
easily tractable blocks ahead of future refactoring.
I'm trying to make `miniooni oonirun -i URL` as possible as
`miniooni -i URL oonirun`, because users typically expect this
kind of flexibity from modern Unix commands.
Part of https://github.com/ooni/probe/issues/2184
