This patch introduces an escript that generates an Erlang .boot script
to start CouchDB using the in-place .beam files produced by the compile
phase of the build. This allows us to radically simplify the boot
process as Erlang computes the optimal order for loading the necessary
modules.

In addition to the simplification this approach offers a significant
speedup when working inside a container environment. In my test with
the stock .devcontainer it reduces startup time from about 75 seconds
down to under 5 seconds.

1. The caching effort was a bust and has been removed. 2) chunkify can be done externally with a custom persist_fun.

All endpoints but _session support gzip encoding and there's no practical reason for that.

This commit enables gzip decoding on compressed requests to _session.