This commit adds two services, `grafana` and `prometheus`, and sets up
some existing services (`dovecot` and `prosody`) to expose metrics into
Grafana. In addition, systemd services have been added to facilitate
registering metrics for services into Prometheus, as well as
automatically provisioning Grafana dashboards based on static JSON
representations.
This work will continue to evolve as more services gain proper Grafana
dashboards, and Loki is also integrated for access to the systemd
journal.
This commit contains a fairly large diff for a fairly small change:
moving the `config/common` directory to `host/base` to better reflect
its intended use, and promoting `config/service` to the root directory.
These changes unlock some improvements in `coreos-home-server-update`
processes, which will (assuming `/etc/coreos-home-server/base` exists)
keep host-wide systemd services in sync in addition to service-specific
ones.
Changes have been make to the `Makefile` and a few other places where
`config/common` was referenced, but most of this work is renames that
are not intended to break compatibility with new or running servers.
