Supporting new load Strategy and minimal bootstrapper for ddc_library_bundle format

[jyameo]

In DWDS, we currently support two load strategies, one for each of the supported module formats: AMD (dwds/lib/src/loaders/frontend_server_require.dart) and DDC (dwds/lib/src/loaders/frontend_server_ddc.dart). We now have a new module format (tentatively called DDC Library Bundle), hence we want a new load strategy to support working with this new format.

[jyameo]

#2523 (review)

[srujzs]

Going to mark this as closed for now. We can track the work to add more stuff to the strategy and support hot restart in the other bugs.