Python Virtual Environment Support

[Martin-Molinero]

• For live & backtest deployments add support for specifying a python virtual environment LEAN should use. This can be achieved by setting the "python-venv" config value for Lean.

• Current available envs are:

  • AMD64 default Foundation-Py-Default, Foundation-Pomegranate & Foundation-Tensorforce see https://github.com/QuantConnect/Lean/blob/master/DockerfileLeanFoundation.
  • ARM64 default Foundation-Py-Default, Foundation-Pomegranate see https://github.com/QuantConnect/Lean/blob/master/DockerfileLeanFoundationARM

Note that for the default environment Foundation-Py-Default, "python-venv" should be empty/not set since it's the system wide env.