esm: implement import.meta.command
This implements a new import.meta.command
as an alternative naming for import.meta.main
. The justification for renaming is clarity in the definition of when this property applies for a given module, after the extensive discussion in https://github.com/nodejs/node/issues/49440.
The specification for this field is provided at the same time to the WinterCG repo for import.meta
in https://github.com/wintercg/import-meta-registry/pull/4.