cli: list-task --after/--before/--all

allow querying for closed tasks

Fixes: https://pagure.io/koji/issue/2565

tests/test_cli/test_list_tasks.py

@@ -22,6 +22,9 @@ class TestListTasks(unittest.TestCase):
         options.method = None
         options.channel = None
         options.host = None
+        options.before = None
+        options.after = None
+        options.all = False
         session = mock.MagicMock(name='session')
         session.getLoggedInUser.return_value = {'id': 1, 'username': 'name'}
         session.listTasks.return_value = []
@@ -259,4 +262,11 @@ Options:
   --channel=CHANNEL  Only tasks in this channel
   --host=HOST        Only tasks for this host
   --quiet            Do not display the column headers
+  --before=BEFORE    List builds built before this time, time is specified as
+                     timestamp or date/time in any format which can be parsed
+                     by dateutil.parser. e.g. "2020-12-31 12:35" or "December
+                     31st 12:35"
+  --after=AFTER      List builds built after this time (same format as for
+                     --before
+  --all              List also finished tasks (valid only with --after)
 """ % self.progname)