This exports Pigweed package in both ESM and UMD formats.
ESM is great for node and modern browsers while UMD offers better
compatibility and ease of use at the expense of being bigger in size.
Separately, this also exports a ProtoCollection with useful protos
(like Echo RPC) which helps downstream user to get started faster.
Change-Id: I13d2625a93d176f5186a2f08dcff5a4585fe4b72
Reviewed-on: https://pigweed-review.googlesource.com/c/pigweed/pigweed/+/102132
Reviewed-by: Anthony DiGirolamo <tonymd@google.com>
Commit-Queue: Asad Memon <asadmemon@google.com>
