Adding a dockerfile using conda enviroment to manage the dependencies.

[mattions]

DockerFile to create docker image of limx.

The dependencies are managed via conda, and stored in the environment.yml

@fpcasale Is there a command line that we can invoke to test if it runs ok in the docker image?

[fpcasale]

@mattions all unit-tests can be run using the setup.py python setup.py test