Like we did before for the resolver, a dialer should propagate the
request to close idle connections to underlying types.
See https://github.com/ooni/probe/issues/1591
Auto-configure every relevant TLS field as close as possible to
where it's actually used.
As a side effect, add support for mocking the creation of a TLS
connection, which should possibly be useful for uTLS?
Work that is part of https://github.com/ooni/probe/issues/1505
* refactor(netx/dialer): hide implementation complexity
This follows the blueprint of `module.Config` and `nodule.New`
described at https://github.com/ooni/probe/issues/1591.
* fix: ndt7 bug where we were not using the right resolver
* fix(legacy/netx): clarify irrelevant implementation change
* fix: improve comments
* fix(hhfm): do not use dialer.New b/c it breaks it
Unclear to me why this is happening. Still, improve upon the
previous situation by adding a timeout.
It does not seem a priority to look into this issue now.
