Introduce an "event bus"-like system. It's more like a fan-out
broadcaster for certain events. Instead of directly sending events to
SocketIO, they are now sent to the broker, which in turn sends it to any
registered "forwarder". Currently there is ony one forwarder, for
SocketIO.
This opens the door for a proper MQTT client that sends the same events
to an MQTT server.
Change the package base name of the Go code, from
`git.blender.org/flamenco` to `projects.blender.org/studio/flamenco`.
The old location, `git.blender.org`, has no longer been use since the
[migration to Gitea][1]. The new package names now reflect the actual
location where Flamenco is hosted.
[1]: https://code.blender.org/2023/02/new-blender-development-infrastructure/
Tasks that are in state `active` but haven't been 'touched' by a Worker
for 10 minutes or longer will transition to state `failed`.
In the future, it might be better to move the decision about which state
is suitable to the Task State Machine service, so that it can be smarter
and take the history of the task into account. Going to `soft-failed`
first might be a nice touch.
