This PR adds a new locking service that keeps track of which local databases are currently in use by the server. If a database is in use due to a running task, immediate calls will now be rejected.
Prior to this change, immediate calls could interfere with the running task, causing a backup to fail abruptly if the user attempted to check the logs or restore.
This PR has a large blast radius because it takes the final step and bumps up the Controller to be fully async.
We have historically done a piece-by-piece update, so all operations were already async but the controller interface was kept synchronous.
With this update, the controller is now fully async and all tests are updated.
Most places where the new C# compiler warns about function names not ending in `Async` were also adressed, giving a massive refactor change.
Functionally, no changes are done.
This removes the WorkerThread class and many of the complications around it.
Instead of having a generic worker, there is now the `QueueRunnerService` which takes on all the resposibilities for handling queued tasks.
This is one step towards removing `FIXMEGlobal`
Kenneth Skovhede