+ neondatabase/cloud#1103
This adds a couple of control endpoints to simplify compute state
discovery for control-plane. For example, now we may figure out
that Postgres wasn't able to start or basebackup failed within
seconds instead of just blindly polling the compute readiness
for a minute or two.
Also we now expose startup metrics (time of the each step: basebackup,
sync safekeepers, config, total). Console grabs them after each
successful start and report as histogram to prometheus and grafana.
OpenAPI spec is added and up-tp date, but is not currently used in the
console yet.
Currently it's included with minimal changes and lives aside of the main
workspace. Later we may re-use and combine common parts with zenith
control_plane.
This change is mostly needed to unify cloud deployment pipeline:
1.1. build compute-tools image
1.2. build compute-node image based on the freshly built compute-tools
2. build zenith image
So we can roll new compute image and new storage required by it to
operate properly. Also it becomes easier to test console against some
specific version of compute-node/-tools.
