enable or disable import-map resolution.
specify a global import-map for aliases to resources.
the full import-map within the body of the resolver function will be a merger between this global import-map, and the import-map acquired from the plugin data (i.e. CommonPluginData.importMap). the plugin data's import-map will take a higher priority in case of conflicting key (i.e. same alias key but different absolute path values).
the resolve function will always look for a match for args.path inside of the import-map,
before resolving it with respect to the current importer or resolve-directory (i.e. args.importer or args.resolveDir).
configuration for the import-map resolver in resolverPluginSetup, which operates on the CommonPluginData.importMap plugin-data property.