These are related things, but somewhat separate. This change should make it
easier to deal with changes regarding querying build servers, and querying
substitute servers.
This allows easily processing an individual job by id. This may be useful to
use manually, but also when processing jobs in parallel, as forking doesn't
work well with the libpq library used by squee.
This is a service designed to provide information about Guix. At the
moment, this initial prototype gathers up information about packages,
the associated metadata and derivations.
The initial primary use case is to compare two different revisions of
Guix, detecting which packages are new, no longer present, updated or
otherwise different.
It's based on the Mumi project.
[1]: https://git.elephly.net/software/mumi.git
