Add ECMA-proposal for "defered module evaluation" as a load strategy

[TomStrepsil]

tc39/proposal-defer-import-eval is an TC39 proposal for deferring javascript execution, implemented experimentally in Webpack here - see documentation

#38 introduces "load strategies", but the "deferred require" strategy is a Common-JS thing. It would be nice to support those that which to have the same capability in ESM.