feat: allow plain domain in dcaccount: scheme

This is similar to old `dcaccount:` with URL,
but creates a 9-character username on the client
and avoids making an HTTPS request.

The scheme is reused to avoid the apps
needing to register for the new scheme.

`http` support is removed because it was
not working already, there is a check
that the scheme is `https` when the URL
is actually used and the core has
no way to make HTTP requests without TLS.

deltachat-rpc-client/src/deltachat_rpc_client/pytestplugin.py

@@ -45,8 +45,8 @@ class ACFactory:
         """Create a new configured account."""
         addr, password = self.get_credentials()
         account = self.get_unconfigured_account()
-        params = {"addr": addr, "password": password}
-        yield account.add_or_update_transport.future(params)
+        domain = os.getenv("CHATMAIL_DOMAIN")
+        yield account.add_transport_from_qr.future(f"dcaccount:{domain}")
 
         assert account.is_configured()
         return account