Install docker and openssh-client during image build.

[Jafner]

Is your feature request related to a problem? Please describe.
Attempting to run docker or ssh-based actions without installing these two fails.

Describe the solution you'd like
Add dnf install -y docker && dnf install -y openssh-client to Dockerfile.

Describe alternatives you've considered
Manually installing these services after the image has been deployed requires re-installation each time the container is created. In my use-case, where Docker Compose is used to statically define the container's configuration, adding a step after deployment is poor practice.

Additional context
I love OliveTin, and I hope I can contribute to its betterment.

[jamesread]

I gave this some re-thinking since it was mentioned in #12.

Using docker and ssh is a very common use case for OliveTin, and because the docker images are provided as a convenience, it makes sense to make them as convenient as possible.

Added in the latest updated container images that have now been published.

Thanks for the comment. :-)