kea_command: new module to access an ISC KEA server
This module can be used to access the JSON API of a
KEA DHCP4, DHCP6, DDNS or other services in a generic
way, without having to manually format the JSON, with
response error code checking.
It directly accesses the Unix Domain Socket API so it
needs to execute on the system the server is running,
with superuser privilegues, but without the hassle of
wrapping it into HTTPS and password auth (or client
certificates).
The integration test uses a predefined setup for
convenience, which runs on Debian trixie as well as,
on the CI, Ubuntu noble. It makes assumptions about
the default package configuration and paths and is
therefore tricky to run on other distros/OSes. This
only affects running the KEA server as part of the
tests, not the module.