Which ought to replace etcd. This patch only adds the binary and adjusts
Dockerfile to include it; subsequent ones will add deploy of helm chart and the
actual replacement.
It is a simple and fast pub-sub message bus. In this patch only safekeeper
message is supported, but others can be easily added.
Compilation now requires protoc to be installed. Installing protobuf-compiler
package is fine for Debian/Ubuntu.
ref
https://github.com/neondatabase/neon/pull/2733https://github.com/neondatabase/neon/issues/2394
