Add the possibility to connect via ssh to a remote docker node.

[tbocek]

This PR also upgrades to the latest github.com/docker/docker where a custom client.WithDialContext can be set (docker/go-connections does not support it). This makes it possible to use dry with: dry -H ssh://user@ip:22/var/run/docker.sock

[moncho]

Pretty awesome, @tbocek!! Thanks a lot for the PR.

Checks are failing, the TravisCI one because it was using an old go version but the GH action is failing because of a test that is not passing: https://github.com/moncho/dry/runs/3985165788#step:4. Could you please take a look at it?

Also, it would be good if you could rebase master onto your branch to fix the problem with the TravisCI build.

[tbocek]

Oops, I thought my changes were not that invasive, but I'm using the latest docker dependency and the docker interfaces changed a bit.

[tbocek]

Hmm, I did not rebase, but the problem seems to be with linting, however, the output says:

golangci-lint found no issues
Ran golangci-lint in 11725ms the GH action

I also tried to check with golangci-lint 1.42.1, and this shows up with many errors.

[moncho]

LGTM