This moves the throttle support to the StreamUtil throttled stream, which allows multiple streams to share a throttle value, such that the throttle setting is applied to the entire communication from Duplicati, and not for each connection.
This also cleans up a bit in the progress reporting, where the backend manager now keeps track of the "active" transfer and only emits progress on that. Once it finishes, a new transfer is promoted a "active".
* Simplified task control by having all logic in a single class and using async control mechanism
* Fixed the tests
* Made the marking of a backup partial explicitly communicated if the enumeration process is stopped.
* Added support for pausing active transfers
* Introduced transfer token to abort operations.
* Updated the way LiveControl is emitting events.
* Retains the paused state of the server across reboots, this fixes#5760.
* Reworked the way throttle speeds are propagated through LiveControls.
* Added option to pause transfers in the UI.
* Removed throttle settings from the LiveControls class so it is exclusively handled by the ApplicationSettings.
* Removed `thread-priority` as it does not work at all when tasks are used.
* Fixed the stop dialog and API to only support stop and abort.
* Removed unused variables