A short blurb per service with its enable option and a link to its section
or page, so an operator on a single host can see what each one is and which
two (builder, CI runner) are worth a look before switching on.
Adds host.json (hive and host filters over the hostmetrics series),
registers it in the provisioned dashboard list, lists it in the swarm
services handbook, and adds a module-eval case that it ships and every
query filters on both variables.
Every docs directory moves under 1-getting-started, 2-handbook,
4-implementation or 5-project; the options reference (section 3) comes from
the website and has no directory here. trust-boundary stays whole under the
handbook for now. web-ui, swarm and tools split between handbook and
implementation, and the command-line references move to
2-handbook/reference. Links, path references in code and nix, and the docs
index follow the moves; no page content changes.
