* feat: create tunnel inside NewSession
We want to create the tunnel when we create the session. This change
allows us to nicely ignore the problem of creating a tunnel when we
already have a proxy, as well as the problem of locking. Everything is
happening, in fact, inside of the NewSession factory.
Modify miniooni such that --tunnel is just syntactic sugar for
--proxy, at least for now. We want, in the future, to teach the
tunnel to possibly use a socks5 proxy.
Because starting a tunnel is a slow operation, we need a context in
NewSession. This causes a bunch of places to change. Not really a big
deal except we need to propagate the changes.
Make sure that the mobile code can create a new session using a
proxy for all the APIs we support.
Make sure all tests are still green and we don't loose coverage of
the various ways in which this code could be used.
This change is part of https://github.com/ooni/probe/issues/985.
* changes after merge
* fix: only keep tests that can hopefully work
While there, identify other places where we should add more
tests or fix integration tests.
Part of https://github.com/ooni/probe/issues/985
* feat(tunnel): introduce persistent tunnel state dir
This diff introduces a persistent state directory for tunnels, so that
we can bootstrap them more quickly after the first time.
Part of https://github.com/ooni/probe/issues/985
* fix: make tunnel dir optional
We have many tests where it does not make sense to explicitly
provide a tunnel dir because we're not using tunnels.
This should simplify setting up a session.
* fix(tunnel): repair tests
* final changes
* more cleanups
