Server / IPFS support for blocks fetched

Needed for both CLI progress and any in-app feedback to publish.

Details on Webnative SDK progress on publish: https://talk.fission.codes/t/webnative-progress-on-publish/2044

Resources

• https://github.com/yamadapc/haskell-ascii-progress
• https://docs.servant.dev/en/stable/tutorial/Server.html#streaming-endpoints