SocketIO clients no longer automatically subscribe to the jobs updates.
This is now done explicitly via the `allJobs` subscription type, and
unsubscribing is also possible.
Add a small wrapper around github.com/google/uuid. That way it's clearer
which functionality is used by Flamenco, doesn't link most of the code to
any specific UUID library, and allows a bit of customisation.
The only customisation now is that Flamenco is a bit stricter in the
formats it accepts; only the `xxxxxxxx-xxxx-xxxx-xxxx-xxxxxxxxxxxx` is
accepted. This makes things a little bit stricter, with the advantage
that we don't need to do any normalisation of received UUID strings.
Implement task log broadcasting via SocketIO. The logs aren't shown in the
web interface yet, but do arrive there in a Pinia store. That store is
capped at 1000 lines to keep memory requirements low-ish.
Manager now sends out task updates via SocketIO, and the web interface
handles those.
Note that there is a `BroadcastTaskUpdate()` function, but not a
`BroadcastNewTask`. The 'new job' broadcast is sent after the job's
tasks have been created, and thus there is no need for a separate
broadcast per task.
SocketIO clients can now send a message with `/subscription` event type
in order to subscribe to or unsubscribe from job-related updates.
These job-related updates themselves aren't sent yet, so this is a change
that's impossible to really test. The socketIO code for joining/leaving
rooms is called, though.
