Suggestion: configurable permanent packages

[AlbertDeFusco]

Right now the conda self reset command only allows conda and its direct dependencies to remain in the env. It might be nice if this could be influenced by reading from a key in condarc, perhaps like

self_additional_permanent_packages:
  - anaconda-anon-usage
  - conda-self

conda-self/conda_self/constants.py

Line 3 in 0dfc22c

PERMANENT_PACKAGES: Final = ("conda",)

[jaimergp]

Right now (taking into account #61), conda plugins are also protected, but maybe we can add a plugin setting for the context.