Copy minimesosFile into the minimesos-cli container

[EarlGray]

Previously, the minimesos-cli container relied on minimesosFile present
in the host's $MINIMESOS_HOST_DIR mounted inside the container. This works
for a local docker daemon, but fails with remote docker daemons (e.g.
docker-machine), because $DOCKER_CONTAINER:$MINIMESOS_HOST_DIR/minimesosFile
is a fresh directory if it does not exist in the [remote] host file system.

Now minimesosFile is copied into $DOCKER_CONTAINER:/minimesosFile and
minimesos-cli is configured with a new system property that points to this
location.

This should fix #546

[EarlGray]

I hope that fixes #538 too.

[frankscholten]

@EarlGray I tried building your branch with

./gradlew buildDockerImage

but I got the following error:

:cli:buildDockerImage FAILED

FAILURE: Build failed with an exception.

* What went wrong:
Execution failed for task ':cli:buildDockerImage'.
> java.lang.reflect.InvocationTargetException-->null

[EarlGray]

I was able to reproduce the build error on Mac (on my branch and on the upstream master too). You can disregard it for checking my changes: if you have Docker for Mac running, the minimesos-cli docker image is actually built and runs successfully via bin/minimesos.

[frankscholten]

LGTM