Add in-app speaker discovery and connection guide

tests/test_imports.py

@@ -9,7 +9,7 @@ class ImportTests(unittest.TestCase):
     def test_headless_import_and_help(self):
         script = """
 import sys
-from controller import protocol, session, messages, cli
+from controller import protocol, session, messages, discovery, cli
 assert 'tkinter' not in sys.modules
 assert 'bleak' not in sys.modules
 try: