The service auto-starts on the system bus with the help of systemd and
bus activation. The service exposes the Maker, Model and update Stream
properties as well as a pair of methods UpdateStreams and UpdateDevices,
neither of which is really implemented.

There's some initial scaffolding for testing using `go test` and
`spread`, both of which are described by the configuration file.

There's also initial REUSE compliance, although for the full experience
one needs unreleased zmk, which makes zmk,  and the files it generates,
reuse compliant. This is not enforced in CI yet.

Signed-off-by: Zygmunt Krynicki <zygmunt.krynicki@huawei.com>