Create platform-independent conda environments

[bakhtos]

Currently, all packages with specific builds are exported to yml files.
These environments cannot be built on osx platform

It is possible to list only explicitly installed packages, allowing conda to find dependencies of dependencies by itself
https://docs.conda.io/projects/conda/en/latest/user-guide/tasks/manage-environments.html#exporting-an-environment-file-across-platforms

[mmantyla]

Done for the no_dl environment. @jnyyssol could you produce this for the full thing if you get it working.