Add ssltransport for robovacs (#943)

This PR implements a clear-text, token-based transport protocol seen on
RV30 Plus (#937).

- Client sends `{"username": "email@example.com", "password":
md5(password)}` and gets back a token in the response
- Rest of the communications are done with POST at `/app?token=<token>`

---------

Co-authored-by: Steven B. <51370195+sdb9696@users.noreply.github.com>

tests/test_cli.py

@@ -692,6 +692,8 @@ async def test_credentials(discovery_mock, mocker, runner):
             dr.device_type,
             "--encrypt-type",
             dr.mgt_encrypt_schm.encrypt_type,
+            "--login-version",
+            dr.mgt_encrypt_schm.lv or 1,
         ],
     )
     assert res.exit_code == 0