Revert "Will use a downloader thread directly from peertube.py. Will not use a service anymore."

This reverts commit 5f590f48cd.

In the end, a service is needed: The addon is ended when kodi starts playing the file, so the
downloader thread would be ended also. I need to launch the downloader thread from something that
isn't expected to end, which is why services exist.

addon.xml

@@ -6,6 +6,8 @@
   <extension point="xbmc.python.pluginsource" library="peertube.py">
     <provides>video</provides>
   </extension>
+  <extension point="xbmc.service" library="service.py"/>
+  </extension>
   <extension point="xbmc.addon.metadata">
     <summary lang="en_GB">Plugin for PeerTube</summary>
     <description lang="en_GB">PeerTube is a federated open source alternative to YouTube</description>

service.py

@@ -0,0 +1,10 @@
+import time
+import xbmc
+
+if __name__ == '__main__':
+    monitor = xbmc.Monitor()
+    
+    while not monitor.abortRequested():
+        if monitor.waitForAbort(1):
+            # Abort was requested while waiting. We must exit
+            break