subtests.docker_daemon: Adds tests for connection with certificate.

Tests generates certificates and sign them up with created CA certificate,
then test connect server and client part with different configurations.

Signed-off-by: Jiří Župka <jzupka@redhat.com>
Oh man, I will be super-duper happy if docker Autotest is still running after 10-years :grinning: I wonder what computers will look like :smile: