Add Daemon restart test along with Daemon utils

This PR allows writing tests that need a daemon restart. It uses hack/dind.
There is also a very useful test case that can also serve as an example on how to use it.

Ping @unclejack @tianon @vieux
I won't need to use hack/dind in the coming update of this PR. But still, it worked fine with sh. However if we want to change this it will be in a separate PR.