[Proposal] Official Conda Support

[jkterry1]

Eventually, I would like to have native Conda support for Gym. This will have to come after the merging of ALE-Py and the planned replacement of the box2d and MuJuCo physics engines discussed in other issues (because they're unmainted and getting them into Conda would be challenging). This will also require very active development from a single maintainer to sort out due to package dependencies. I'm mostly putting this on GitHub so I don't forget in 9 months.

[h-vetinari]

Note that there exists packaging by conda-forge for gym since more than a year: https://github.com/conda-forge/gym-feedstock

Due to the addition of ALE-py as a dependency (which hasn't been packaged yet for conda-forge), this is currently not up-to-date with the most current version, but that should be rectified soon-ish.

Also, MuJoCo will most likely never be compatible for packaging in conda-forge, unless the upstream license is changed to something free.

MuJoCo notwithstanding, I recommend not packaging this into a separate channel. Channels other than conda-forge & anaconda defaults have no interoperability guarantees (e.g. using different package versions of ABI-sensitive packages for compilation & runtime might lead to crashes), and in general, the recommendation is to have as few channels as possible. Conda-forge even recommends conda config --set channel_priority strict which means that anyone following a best practice setup would never get packages from a putative openai channel, because the packages already available in conda-forge would take precedence.