install_mlflow() requires Python and Conda to be installed.
See https://www.python.org/downloads/ and https://docs.conda.io/projects/conda/en/latest/user-guide/install/.
Alternatively, you can set MLFLOW_PYTHON_BIN and MLFLOW_BIN environment variables
instead. MLFLOW_PYTHON_BIN should point to python executable and MLFLOW_BIN to mlflow cli
executable. These variables allow you to use custom mlflow installation. Note that there may be
some compatibility issues if the custom mlflow version does not match the version of the R
package.