Since the machine drivers are hardcoded in minikube,
drivers need to be added to the registry to be tested.

Add a basic sanity check for the qemu-system binary,
and set up the basic configuration such as cpus/memory.

Copy some of the default values from the regular setup,
that is not used when not using docker-machine config.

Only the SSH and the Docker port (2376) are available
with the slirp network, everything else needs tunneling.

It is still ancient, so there is bound to be issues
with the vendored code from libmachine and drivers.

This is an internal driver, with the new driver config
rather than the machine flags of the external driver.

Assume "user" networking, for now at least.

This reverts commit e7495ab.

…emu2

…emu2