update docs to indicate that micromamba and mamba are recommended over conda

[zacharyburnett]

in response to the Anaconda ToS changes:
https://legal.anaconda.com/policies/en/#:~:text=2.1%20Organizational%20Use.%C2%A0

2.1 Organizational Use. Your registration, download, use, installation, access, or enjoyment of all Anaconda Offerings on behalf of an organization that has two hundred (200) or more employees or contractors ("Organizational Use") requires a paid license. For sake of clarity, use by government entities and nonprofit entities with over 200 employees or contractors is considered Organizational Use. Educational Entities will be exempt from the paid license requirement, provided that the use of the Anaconda Offering(s) is solely limited to being used for a curriculum-based course. Anaconda reserves the right to monitor the registration, download, use, installation, access, or enjoyment of the Anaconda Offerings to ensure it is part of a curriculum. Utilizing Miniconda to pull package updates from the Anaconda Public Repository without a commercial license (if required by the conditions set forth in Section 2 of this Terms of Service) is considered a violation of the Terms of Service.

[zacharyburnett]

docs for this PR hosted at https://stenv--153.org.readthedocs.build/en/153/