To untie cyclic dependency between sync and async versions of postgres_backend,
copy QueryError and some logging/error routines to postgres_backend.rs. This is
temporal glue to make commits smaller, sync version will be dropped by the
upcoming commit completely.
Closes https://github.com/neondatabase/neon/issues/3114
Adds more typization into errors that appear during protocol messages (`FeMessage`), postgres and walreceiver connections.
Socket IO errors are now better detected and logged with lesser (INFO, DEBUG) error level, without traces that they were logged before, when they were wrapped in anyhow context.
* Support configuring the log format as json or plain.
Separately test json and plain logger. They would be competing on the
same global subscriber otherwise.
* Implement log_format for pageserver config
* Implement configurable log format for safekeeper.