Improve cache loading time at launch

When loading cache, time is lost in yui Event loop, instead of giving priority to heavy CPU consumming threads. In these cases, the change commute to a lower timeout, which can improve the loading time dividing it by 5.
If we load cache outside a thread, the UI becomes unresponsive.

Author: papoteur-mga

dnfdragora/ui.py

@@ -1417,7 +1417,11 @@ def handleevent(self):
         """
         self.running = True
         while self.running == True:
-            event = self.dialog.waitForEvent(200)
+            loop_timeout = 20 if  self._status in (DNFDragoraStatus.CACHING_AVAILABLE, \
+                    DNFDragoraStatus.CACHING_UPDATE, \
+                    DNFDragoraStatus.CACHING_INSTALLED) \
+                    else 200
+            event = self.dialog.waitForEvent(loop_timeout)
 
             eventType = event.eventType()