[ALOY-1694] app/lib files do not have sourceMappingURL comments

The way that Alloy copies lib/ files results in source maps being generated, but the copied lib file has no pointer to the source map. It should have a //# sourceMappingURL= comment appended which points to the full file path of the generated source map file. Additionally, the generated source maps **may not be correct** based on the optimizer plugin being run as a post-process "Optimizer" step. Ideally the files should be processed by Babel, spit out a source map, have a comment appended to the generated contents pointing at the map file, and then written to disk (all as a single process/flow per-file) and not included in the later "optimizing" step. Instead Alloy does this: - copies the file as-is (no //# sourceMappingURL= comment!) - immediately generates a 1:1 source map to represent the copy - later runs an "optimizing step" on some of the files under the Resources/ directory (including the ones from lib/!) which **may** result in the source map now being incorrect