[Enhancement] Automatic reconnect on error

[schlagmichdoch]

What problem is solved by the new feature
Sometimes the WebRTC connection throws an error which results in a disconnection of devices and abort of transfers. They only connect again after one client has reloaded the page.

Describe the feature
On error, queue messages, try to reconnect 10 times with 0.5s delay and continue if connection is reestablished. Only then abort connection.