Django migration: #47 (closed).
This MR re-adds the debian-qa plugin.
Interaction with tracker.d.o has been moved to two debexpo.tools.clients.tracker classes. One for requesting the data and the other to parse to make the response available.
Namely, ClientTracker() and TrackerPackage().
The two unimplemented methods _test_has_new_maintainer() and _test_previous_sponsors() have been removed.
New dependency added for html parsing: python3-lxml
Offline tests cover this plugin.