Sync against taskchampion-sync-server (#3118)

This removes use of gnutls and the TLS implementation, which is no
longer needed (task synchronization is handled via Taskchampion, which
uses `reqwest`, which handles TLS via other Rust dependencies). This
incidentally removes the following config options:
 * `debug.tls`
 * `taskd.ca`
 * `taskd.certificate`
 * `taskd.ciphers`
 * `taskd.credentials`
 * `taskd.key`
 * `taskd.server`
 * `taskd.trust`

test/template.t

@@ -34,7 +34,6 @@ from datetime import datetime
 sys.path.append(os.path.dirname(os.path.abspath(__file__)))
 
 from basetest import Task, TestCase
-from basetest import Taskd, ServerTestCase
 
 
 # Test methods available:
@@ -226,25 +225,6 @@ sys.exit(0)
                          "This is an example modify hook")
 
 
-class ServerTestBugNumber(ServerTestCase):
-    @classmethod
-    def setUpClass(cls):
-        cls.taskd = Taskd()
-        # This takes a while...
-        cls.taskd.start()
-
-    def setUp(self):
-        """Executed before each test in the class"""
-        self.t = Task(taskd=self.taskd)
-        # Or if Task() is already available
-        # self.t.bind_taskd_server(self.taskd)
-
-    def test_server_sync(self):
-        """Testing if client and server can speak to each other"""
-        self.t("add Something to sync")
-        self.t("sync")
-
-
 if __name__ == "__main__":
     from simpletap import TAPTestRunner
     unittest.main(testRunner=TAPTestRunner())