Recommend mambaforge?

[maxnoe]

Readme recommends a full anaconda install and then install mamba and creating an environment.

This has several problems in my experience:

• a lot of wasted space for the full anaconda env
• A large base env will inadvertently make upgrading conda/mamba hard due to "solving environment" issues
• Installing mamba itself might fail due to conda being slow solving the large environment with all the packages in conda-forge

Solution: Let people install mambaforge (Miniconda with preinstalled mamba from: https://github.com/conda-forge/miniforge#mambaforge)