Error handling in Conda Package Manager

[GeorgSchulz]

Currently the Conda Package Manager in JupyterLab can be used for updating existing packages and adding new packages to the provided default JupyterLab Anaconda environments.

However, new environments can not be created using JupyterLab. Additionally, the error "An error occurred while retrieving available packages." can be seen in the Conda Package Manager (see e.g.: https://conda.continuum.narkive.com/cAoA05Yu/another-jupyter-tab-error-an-error-occurred-while-retrieving-package-information).