Monitor and Process downloads separately

New: Queue remains up to date while importing file from remote file system
Fixed: Failed downloads still in queue won't result in failed search

Closes #668
Closes #907
Fixes #2973

frontend/src/Components/SignalRConnector.js

@@ -262,7 +262,7 @@ class SignalRConnector extends Component {
   }
 
   handleSystemTask = () => {
-    // No-op for now, we may want this later
+    this.props.dispatchFetchCommands();
   }
 
   handleRootfolder = () => {