* Rename wal_acceptor binary to safekeeper
* Rename wal_acceptor.pid and wal_acceptor.log to safekeeper.pid and safekeeper.log
* Change some mentions of WAL acceptor to safekeeper
* Dockerfile: alias wal_acceptor to safekeeper temporarily until internal scripts are updated
The dockerignore and dockerfile have also been excluded from being moved into
docker images, saving docker layer cache busts if only those are changed.
* make .dockerignore `ncdu -X` compatible to easily inspect build context
* remove cargo-chef as it was introducing more problems than it was solving
* remove rocksdb packages
* add ca-certs in the resulting image. We need that to be able to make https
connections from container with proxy to the console.
