Add a Worker configuration option to configure the Linux out-of-memory
behaviour. Add `oom_score_adjust=500` to `flamenco-worker.yaml` to increase
the chance that Blender gets killed when the machine runs out of memory,
instead of Flamenco Worker itself.
The worker-written config files would all refer to
`flamenco-worker-example.yaml`, even though this file doesn't even
exist. Instead, the configuration file will refer to the appropriate
documentation on the website, and the credentials file will explain what
happens when you delete it.
The credentials are otherwise intentionally left undocumented, as their
contents are not to be manually edited. The only thing to do with that
file is delete it so that the Worker re-registers itself at startup.
Create a dedicated package `.../pkg/website` to contain constants for the
URLs of documentation, bug reporting, etc. That way it's easier to see
which parts of the website are being referred to from the Flamenco
binaries, and updates can happen in a central spot.
No functional changes.
