Use Conda.jl for environment handling

[THinnerichs]

We should do the following to install and handle the Python environment from Julia (and not just assume the correct installation):

An alternative is to configure PyCall to use a Julia-specific Python distribution via the Conda.jl package (which installs a private Anaconda Python distribution), which has the advantage that packages can be installed and kept up-to-date via Julia. As explained in the PyCall documentation, set ENV["PYTHON"]="", run Pkg.build("PyCall"), and re-launch Julia. Then, to install the torch module, you can use pyimport_conda("torch", PKG), where PKG is the Anaconda package that contains the module torch, or alternatively you can use the Conda package directly (via using Conda followed by Conda.add etcetera).

[IssaHanou]

You can also use the following code to add packages using pip:

using Conda, PyCall

Conda.pip_interop(true)
Conda.pip("install", "{package}")