Async process progress (smb sync)

[raffis]

Is your feature request related to a problem? Please describe

Balloon implements a task queue in order to run tasks unrelated to http requests.
However it is required that one can retrieve the status of a process #298 which is currently not possible. Once a task has been created it is a black hole for the client.
Only the server itself knows the status of a process.

For example:
One adds an external smb storage. Balloon triggers a process to sync that very storage. The client will have absolutely no information about the progress of that process.

Describe the solution you'd like

• Implement progress updates in \TaskScheduler
• Push progress updates to clients via wss pub/sub message queue wss push updates #365
• Publish process information via rest api endpoints Add api endpoint to get information about async processes #298

Describe alternatives you've considered

I have no alternative in mind.

Additional context

Add any other context or screenshots about the feature request here.