Do not shipping records over the inter-node wire

Originally by @chewbranca

We now depend on Erlang 17 minimum, and can easily move up to 19 or 20 if desired.

We could possibly look at this now using maps or versioned records.

/cc @rnewson @davisp

The issue names no files, tests, or entry points, so first locate the inter-node wire serialization path in CouchDB. Review the Erlang 17–20 compatibility context and the proposed maps or versioned records approach; done should mean a defined, tested way to avoid shipping records between nodes.

Written by the indexing model from the issue text.