bug dashboard: add a stats tab about recent resolved bugs

[markuszoeller]

rough example of how to query the last resolved bugs.

project = launchpad.projects["nova"]

bug_tasks = project.searchTasks(status=['Invalid', 'Opinion', "Won't Fix",
                                        'Fix Released'],
                                order_by='-date_last_updated',
                                omit_duplicates=True)


print "================================================="
print " recent bug actions"
print "================================================="
today = datetime.datetime.today()
counter = 0
for bug_task in bug_tasks:
#    print(bug_task.bug)
    diff = today - bug_task.bug.date_last_updated.replace(tzinfo=None)
    if diff.days > 90:
        break
    # remove the timezone info as it disturbs the calculation of the diff
#     print("days: %d" % diff.days)
#     print "https://bugs.launchpad.net/nova/+bug/" + str(bug_task.bug.id)
    counter += 1
print(counter)