Add support for TalkTalk-branded router (UK)

[mr-miles]

Model information

F5364 from TalkTalk

Describe the bug

GetDeviceInfo is failing because this particular flavour of router doesn't have a ModelNumber.
Otherwise the library is working great!
Impact is that HA is unable to connect to the router since an exception is thrown in the setup.

Expected behavior

I think ModelNumber is not important in the bigger scheme and could be defaulted to blank.

Additional context

I've submitted a PR that fixes this - #386 - and also provides better support for ActionErrors when the request contains multiple xpaths.

[bug]