Support miniforge, micromamba, and may be others?

[yarikoptic]

As an alternative/complimentary to

• git-annex -m conda installation fails in CI #206 (comment)

of adding --channels to miniconda, it might be worth adding support for other conda distributions, e.g. miniforge or micromamba which could be leaner / faster, less ambiguous (have a single channel).

@mih when you found that concern on number of inodes used by conda datalad installation, did you look

See https://conda.org/blog/2024-08-14-conda-ecosystem-explained/ for more information on those. FWIW micromamba manager itself is a 14M single executable.

I didn't look either all come from https://github.com/conda/constructor/ and have consistent/compatible interface.

[yarikoptic]

FWIW, micromamba installation of a venv with datalad is still quite a monster (after micromamba clean -a)