With this factory, we want to construct ourselves the TLS dialer
so that we can use a dialer wrapper that always sets timeouts when
reading, addressing https://github.com/ooni/probe/issues/1609.
As a result, we cannot immediately replace the i/e/netx factory
for creating a new HTTP transport, since the functions signatures
are not directly compatible.
Refactoring is part of https://github.com/ooni/probe/issues/1505.
This diff is part of https://github.com/ooni/probe/issues/1505.
You will notice that I have not adapted all the (great) tests we had
previously. They should live at another layer, and namely the one that
deals with performing measurements.
When I'm refactoring such a layer I'll ensure those tests that I have
not adapted here are reintroduced into the tree.
